A bewildering array of technology is available to detect virtually anything – from atoms to galaxies.

Active sensors detect objects by bouncing energy off them and analyzing the returned signal. Radar emits radio or microwaves, sonar uses sound, etc. All such sensors incorporate display panels or terminals that translate the raw data into a comprehensible image.

Active sensors are rated for sensor type and range. Detecting hidden targets or resolving fine detail requires an Electronics Operation roll; the specialty depends on the sensor (see p. B189). This is at no range penalty out to the sensor’s rated range. Each doubling of range beyond that gives -2 to skill.

Rolls are only allowed against targets within the sensor’s arc. Unless otherwise noted, assume that active sensors scan a 120° arc in front of them. In effect, they have No Peripheral Vision.

Specialized detectors within an active sensor’s arc can detect the energy that the sensor emits at up to twice the sensor’s range. The signal doesn’t simply vanish at that distance, of course – sensitive detectors may sense it from much further away. Each type of sensor requires a different kind of detector.

Targeting Mode: Expensive combat-capable or “tactical” sensors incorporate a “target-acquisition” or “fire-control” mode, which works identically for all active sensors: The sensor generates a narrow targeting beam. It requires an Aim maneuver to “lock onto” a target that has already been detected. The sensor then acts as a rangefinder, determining the target’s precise range and speed. This gives +3 to hit with an aimed ranged attack – cumulative with the benefits of targeting software.

Sonar (sound navigation and ranging) uses ultrasonic sound waves to detect underwater objects and determine their general shape. The term is courtesy of the WWII-era U.S. Navy. As far back as 1917, the British called this technology “ASDIC” in honor of the Anti-Submarine Detection Investigation Committee, the group responsible for adopting sound-based standards of submarine detection.

In addition to watching a display screen, most sonar operators wear headphones that let them listen for audible clues about the object being “pinged” by the sonar. Make an Electronics Operation (Sonar) roll to detect or identify an object. Ambient noise from sea life and other ships interferes with detection, giving from -1 when near noisy whales to -6 when trying to detect something in a busy harbor. Sonar can also be “jammed” or fooled by an extremely loud noise (e.g., an explosion).

Individuals or devices with Ultrahearing (p. B94) can detect sonar.

Large Sonar (TL6). A powerful sonar suite and workstation, found aboard military vessels (patrol boats, submarines, etc.) or in a fixed station for harbor defense. Range is 4,000 yards at TL6, 8,000 yards at TL7, and 20,000 yards at TL8. $2,000,000, 1 ton, external power. LC4.

Medium Sonar (TL8). Sonar used by small boats or deep-sea salvage divers. The diver-operated version looks like a scuba tank with a display screen on the rear. Range is 2,000 yards. $15,000, 50 lbs., 12¥L/4 hrs. LC4.

Small Sonar (TL8). A handheld sonar unit that resembles a megaphone. It’s used by divers to detect underwater mines, drowning victims, discarded murder weapons, etc. Range is 100 yards. $2,000, 8 lbs., 8¥S/20 hrs. LC4.

Tactical (TL6). Medium and large sonar can be bought with a military-style targeting mode. This can track and identify up to 10 targets at once out to the listed range, and give +3 to hit any of them with an aimed attack. ¥5 cost. LC2.

Imaging (TL8). At TL8, high-frequency sonar can render fine surface detail rather than merely revealing an object’s general shape. This allows sub-bottom profiling to detect objects beneath the floor of a body of water, much like ground penetrating radar (see right). Range is 1/10 normal. ¥5 cost, ¥2 weight. LC2.

Radar (radio detection and ranging) uses high-frequency radio or microwaves to render an image of a distant object. Britain, Germany, and the U.S. developed it simultaneously and independently in the 1930s. The first true demonstration of radar’s capability was the defeat of the Luftwaffe during the Battle of Britain in 1941, thanks to the Chain Home radar network. Radar has played a significant role in almost every military operation since then. Today’s radars are smaller (often man-portable) and more powerful.

Radar indicates target speed, altitude, position, and approximate size. The GM can assume that radar automatically spots most moving targets that are in range and that fit its criteria. If a target is using radar countermeasures or being stealthy, though, the radar operator must win a Quick Contest of Electronics Operation (Sensors) skill against the Electronics Operation (EW) skill of an intruder with a jammer or the Stealth skill of an infiltrator on foot.

Radar is unimpaired by darkness, smoke, and bad weather, but it can’t see over the horizon, through solid obstacles, or underwater. It can’t discriminate between a moving human and a moving animal or vehicle of similar size. Background items make spotting stationary human-sized or smaller objects on the ground practically impossible in anything but open terrain. Assume that the operator can’t distinguish nonmoving targets from “ground clutter” unless he previously saw that particular “blip” moving.

Large Radar (TL7). A 100-mile range radar station for surface-to-air missile sites, airports, warships, or search aircraft. It consists of a large tower or radome, a cabinet full of equipment, and 1-3 workstations. $1,000,000, 10 tons, external power. LC3.

Medium Radar (TL7). A 15-mile range radar mounted on a tripod or a vehicle. $50,000, 100 lbs., external power. LC3.

Small Radar (TL7). A 3-mile range radar, typical of those found on marine vessels, civilian aircraft, and ground vehicles used by “storm chasers.” $10,000, 30 lbs., external power. LC3.

In all cases, double range and halve weight at TL8.

The radars above (but not ground-penetrating or thru-wall radar) can be bought with these modes:

Low-Probability Intercept (TL8). LPI radar uses rapid, frequency-agile bursts of energy. This halves range, but the signal can only be detected at 1.5 times the halved range (instead of at twice the usual range). ¥5 cost. LC2.

Tactical (TL8). This is military-style targeting radar. It can track up to 10 targets at once out to the listed range, identify their general class at 1/10 that range, and give +3 to hit any of them with an aimed attack. ¥5 cost. LC2.

This is Imaging Radar (p. B81) tuned to produce a subsurface scan that shows the inside of an object. It can locate old roads, burial grounds, buried pipes and wires, caverns, land mines, and long-buried treasure. In 1988, a search team using a GPR successfully located “The Lost Squadron”: a flight of eight Lockheed P-38 fighters abandoned in Greenland in 1942. A recovery crew worked for three months to dig one of the P-38s out of nearly 90 yards of ice. The old warbird, dubbed Glacier Girl, was fully restored and flew again in 2002.

Object detection depends on many factors, including the composition and alignment of the object under scrutiny, and the material around it. In general, a GPR gets ¥20 range in ice but only ¥0.1 range in concrete or rock. A successful Electronics Operation (Scientific) roll can deduce the type of soil or the distance to bedrock, or detect buried items. Suitable software tools (p. 2) can generate 3D images from the data.

Handheld GPR (TL8). A ground-penetrating radar the size of a hardback book. It has a range of 1’. A 2” LCD screen is built into the top of the unit. A digital storage device (p. 22) records data. The internal rechargeable battery lasts for 2 hours. $10,000, 3 lbs. LC4.

Portable GPR (TL8). A shoebox-sized radar unit connected to a color LCD screen. It has a 10-yard range. The operator drags the radar across the ground while watching the screen. The internal rechargeable battery lasts for 2 hours. $50,000, 30 lbs. LC4.

Like ground-penetrating radar, this specially tuned radar can see through solid objects and into the space beyond. An example is the law-enforcement and security tool marketed as Soldier Vision. It can see through a wall a foot thick (wood, brick, gypsum, etc.) and detect a person 20 yards beyond that. Its range is less than 1’ through concrete, however. It uses Electronics Operation (Surveillance) skill. The rechargeable battery lasts 3 hours. $30,000, 10 lbs. LC3.

Throughout TL5-6, “passive visual sensors” means the Mark I Eyeball, assisted by ever-improving optics. At TL7, sensors appear that work like normal vision but extend the limits of human sight. In particular, great advances are made in the area of night vision. The most common feature of passive sensors is telescopic magnification. Each doubling of magnification lets the user ignore -1 in range penalties on Vision rolls while using the sensor. The user can also “zoom in” on a particular target by taking an Aim maneuver, which is useful for making a more precise identification. While doing so, each doubling of magnification cancels -2 in range penalties to see that one target, but the sensor provides no bonus to spot other targets.

When comparing real-world sensors to those described here, note that the listed magnifications represent a simplification of a complicated issue. For most optics, aperture size and eyepiece magnification define performance. Determining the actual power of a telescope is a tricky proposition, and involves aperture size, focal length, focal ratio, etc.

Most of the sensors listed below can accommodate a camera. This is affixed to the eyepiece for non-electronic optics (all TL5-6 hardware). At TL7-8, electronic sensors can be plugged into other electronics using a cable. All of these devices protect the eye(s) behind them with DR 1.

During the Age of Sail, the telescope was a symbol of authority for military officers – especially naval officers. The “spyglass” was a near-constant feature in portraits of such men. Around 1830, binoculars came into use. They replaced the telescope in the field, except for special applications, and were de rigueur among officers in both World Wars.

One danger of optics is lens shine. On a bright day, the telltale glint of field glasses can be seen on a Vision roll. To avoid this, the user must make a Stealth roll. From mid- TL5, hoods that partially obscure the lens are available, granting +4 to Stealth for this purpose. Binoculars (TL5). An officer’s “field glasses.” 4¥ magnification. $100, 4 lbs. LC4.

Spyglass (TL5). A collapsible tube fitted with lenses. Early models were made of brass, often with leather trim. Such a spyglass can be used as a light club – and is fairly well-balanced as a weapon – but will never again be useful as a telescope! 4¥ magnification. Holdout -2. $25, 2 lbs. LC4. Binoculars (TL6). 6¥ magnification. $150, 3 lbs. LC4. Pocket Spyglass (TL6). 4¥ magnification. Holdout -1. $5, 0.25 lb. LC4.

Scissors Telescope (TL6). During the trench fighting of WWI, tripod-mounted stereoscopic telescopes were used for rangefinding and surveillance. They were standard equipment throughout WWII. Called “donkey ears” or “rabbit ears” by the British, these extend 2’ above the observer – well over the ramparts of most earthworks. An optional movie-camera attachment is available. 6¥ magnification. $1,000, 30 lbs. LC4.

Spotting Scope (TL6). A large scope mounted on a small tripod. The observer must either be prone or place both scope and tripod on a bench. 30¥ magnification. $300, 10 lbs. LC4.

Military-Grade Binoculars (TL7). From the 1960s, binoculars such as these are often ruggedized (p. 10). 10¥ magnification. $800, 2.5 lbs. LC4.

Military-Grade Binoculars (TL8). The lenses of modern military binoculars are often coated to protect the eyes from laser light (giving Protected Vision, p. B78) and fitted with anti-reflective screens to reduce lens shine. 10¥ magnification. $800, 3.5 lbs. LC3.

Stabilized Binoculars (TL8). Some advanced civilian binoculars incorporate mechanical stabilization. This eliminates up to -3 in movement penalties – handy when observing from a vehicle. 10¥ magnification. $5,000, 4 lbs. LC4.

The earliest night-vision devices were developed in the 1930s – an accidental discovery made during work on television cameras. They were monstrous cabinets that popped and hissed, and produced little more than a blurry image. During WWII, the British, Germans, and Americans all developed their own night-vision equipment, which was further refined throughout the Cold War. Modern systems are lightweight and cheap. They’re an essential military and police tool, but also used by wildlife-management personnel, bird watchers, journalists, and sailors.

The devices described below use near-infrared and/or computer-enhanced light-intensification optics to amplify ambient light levels. They’re rated for the level of Night Vision (p. B71) they provide. Each level lets the user ignore -1 in combat or vision penalties due to darkness. This has no effect on the -10 for total darkness, though. Some viewers offer telescopic magnification as well. In all cases, the user has Colorblindness (p. B127), No Depth Perception (p. B145), and No Peripheral Vision (p. B151) while using the optics.

Early Night-Vision Binoculars (TL7). A primitive nightvision viewer like the top-secret British TABBY device used during the Normandy invasion of 1944. It requires an IR illuminator (see IR Illumination, p. 47) to be effective. Gives Night Vision 2. $5,000, 3 lbs., 4¥XS/20 hrs. LC4. Night-Vision Binoculars (TL7). A typical vehicle- or tripod-mounted Cold War surveillance device, used from the Berlin Wall to the jungles of Vietnam. Standard equipment aboard AFVs and warships. Gives Night Vision 4. 16¥ magnification. $15,000, 35 lbs., 4¥XS/20 hrs. LC4. Military Surplus Night-Vision Binoculars (TL8). This is reconditioned “military surplus” hardware, often with older Eastern Bloc components, like that peddled in survivalist magazines. Typically has a built-in IR illuminator (see IR Illumination, p. 47). Gives Night Vision 4. $200, 1 lb., 2¥XS/30 hrs. LC4. Night-Vision Binoculars (TL8). Handheld, long-range night-vision binoculars. Gives Night Vision 9. 16¥ magnification. $6,000, 3 lbs., 2¥XS/20 hrs. LC4. Night Vision Goggles (TL8). Head-mounted goggles – known as “NVGs” or “NODs” – such as the U.S. Army’s AN/PVS-7 series, often worn on a flip-up helmet mount. Early versions were issued to helicopter pilots. Gives Night Vision 7-9. $3,500, 1.5 lbs., 2¥XS/20 hrs. LC4.

Most night-vision optics and thermographs pick up visible and infrared wavelengths. An infrared filter placed over a light source such as a flashlight completely blocks the passage of visible light but permits infrared – which is invisible to the naked eye – to shine through. Night-vision gear within such a source’s normal range can function even in total darkness, and gains two additional levels of artificial Night Vision. However, anybody with night-vision optics or a thermograph will see this “active IR” source as a flashlight or a spotlight, and get +4 to all rolls made to locate it (Vision, Observation, Electronics Operation, etc.).

Thermographs are devices that detect the infrared spectra emitted by objects at different temperatures and then build up a black-and-white (or more rarely, false-color) image of the environment. The first thermographs – called “forward-looking infrared” (FLIR) – were used on helicopters and fixed-wing gunships in Vietnam. Today, infantrymen, police, firefighters, and high-end security systems all benefit from “thermal imaging” technology.

A thermograph lets the user observe or fight at no darkness penalty, even in absolute darkness, if his target emits heat – which is typical of all living beings and most machines and electronics. It gives +2 to all Vision rolls to spot such targets, since their heat stands out from the background. It can also, at no bonus, distinguish targets that are warmer or colder than their surroundings: a running engine, hand prints on a recently handled object, a blood trail in the snow, etc. This grants +3 to Tracking rolls if the trail is no more than an hour old.

Thermal imaging doesn’t distinguish real colors, which may limit the ability to use some controls, and only allows the user to judge the general size and shape of heatemitting objects – including living beings. For instance, a scout might have trouble telling two people of the same size apart. Roll at -4 to distinguish objects of similar size and shape. As well, the GM may require a Vision-4 roll to read by reflected heat.

Thermographs have some other drawbacks, too. A sudden flash of heat (e.g., flare, fiery explosion, or infrared laser) can blind them, just as a flash of bright light can blind ordinary vision. Early thermographs are artificially cooled and need 1-2 minutes to reach operational status after being switched on. At mid-TL8, thermographs do away with the bulky cooling system and can be ready in 3- 5 seconds.

All of the systems below grant the equivalent of Infravision (p. B60), but also give the user Colorblindness (p. B127), No Depth Perception (p. B145), and No Peripheral Vision (p. B151) while in use. Most include some level of telescopic magnification as well.

Thermal-Imaging Sensor (TL7). A long-range thermal telescope of the type found on military aircraft, unmanned aerial vehicles, television helicopters, etc. 32¥ magnification. $40,000, 50 lbs., external power. LC3.

Mini-Thermal Imager (TL8). A pocket-sized viewer that can be mounted on a weapon, or used as a handheld viewer or – with a helmet mount – a hands-free monocular. $10,000, 1 lb., 2¥XS/7 hrs. LC4.

Thermal-Imaging Binoculars (TL8). Used by military, police, border patrols, rescue teams, and others. 8¥ magnification. $7,000, 3 lbs., 4¥XS/4 hrs. LC4.

Thermal-Imaging Goggles (TL8). A thermal-imaging camera mounted on a helmet or a head-strap. 4¥ magnification. $13,000, 1.5 lbs., XS/2 hrs. LC4.

Thermal-Imaging Surveillance Camera (TL8). A security camera for outdoor surveillance. It’s standard equipment at such high-security installations as nuclear power plants. 4¥ magnification. $7,000, 1 lb., external power. LC4.

New weapons and vehicles fielded in the World Wars spur the development of many non-visual passive sensors at TL6. Cold War cat-and-mouse games played with spies, subs, and nukes at TL7 – and efforts to enforce global security at TL8 – ensure that such technologies continue to mature. Except as noted, these detectors are omnidirectional and don’t require a line of sight.

In April 1915, the Germans released over 150 tons of chlorine gas during the Second Battle of Ypres. French and Algerian troops fled in panic, and the German infantry slogged forward into a gap four miles wide. This was the Western Front’s introduction to gas warfare.

At TL6-7, chemical detection relies on reactive papers or powders. At TL8, an “artificial nose” can sniff out chemicals in the atmosphere and notify the operator. Each device is designed to detect a specific class of agents, which might be narrow or very broad.

Chemical Test Kit (TL6). The first detectors are strips of paper treated to react to specific chemicals. They’re worn on the sleeve by hazardous-materials workers and soldiers, dipped in suspicious liquids, etc. At TL6, a positive test means the paper changes color in a minute or two; at TL8, reaction time is instant. A test kit of 50 strips, covering a wide array of chemicals: $25, 0.5 lb. LC4.

Handheld Detector (TL8). This state-of-the-art handheld unit can sense an entire range of dangerous or illicit substances – typically chemical weapons, drugs, or explosives. Detection range is about 1’. $60,000, 6 lbs., 4¥S/12 hrs. LC4.

Portable NBC Detector (TL8). This lunchbox-sized detector automatically sounds an alarm in the presence of any known NBC agent. It can be connected to other sensors to form a perimeter, or monitored remotely from a laptop. Most modern AFVs carry such a detector. $100,000, 15 lbs., M/14 hrs. LC4.

A hydrophone is a sensitive underwater microphone that can detect and track moving or noisy objects in the water. The British used hundreds of them as early as 1911, mostly for navigation; buoys and other navigational aids had bells affixed to the underside so that vessels could get a bearing even in bad weather. By the end of WWII, the Americans were airdropping “sonobuoys” in the Pacific. During the Cold War, the U.S. developed a network of deepocean hydrophones – the Sound Surveillance System (SOSUS) – capable of tracking Soviet nuclear submarines nearly anywhere in the world.

To detect a noisy underwater object, roll against Electronics Operation (Sonar). Most hydrophones give a bonus to this roll (see below). Look up the target’s size, speed, and range separately on the Size and Speed/Range Table (p. B550), and apply bonuses for size and speed, but a penalty for range. Swift currents generate “noise”; find the current’s speed on the table and assess a speed penalty.

Success reveals the target’s location (direction and distance), vector (speed and direction of movement), rough size, and general class based on sounds (e.g., “whale” or “nuclear sub”) – but not shape, color, etc. This information gives +8 to identify the target, +4 to shadow it, and +3 to hit it with an aimed attack. If using a hydrophone fix to direct an attack, the modifiers that applied to the detection roll also apply to the attack roll, but can never give a bonus to hit.

Hydrophones automatically detect sonar (pp. 45-46) and underwater communicators (p. 40) at twice those systems’ range.

Large Hydrophone (TL6). A vehicle-based system – or at TL7-8, a deep-ocean sensor like those that make up SOSUS. +4 detection rolls. $1,000,000, 2,000 lbs., external power. LC3.

Medium Hydrophone (TL6). A typical swimmerdetection system. +2 detection rolls. $50,000, 200 lbs., external power. LC3.

Small Hydrophone (TL7). A compact device, like an airdropped sonobuoy. $5,000, 15 lbs., M/4 hrs. LC2.

The detection bonus increases by +2 for each TL after introduction.

Simple hydrophones are used for underwater research, fishing, and perimeter surveillance. These don’t provide the +3 targeting bonus. Typical TL7-8 trawlers carry small search hydrophones. Divide cost by 10. Raise LC to 4.

The most basic radiation detector is chemically treated film that darkens in the presence of radiation. During the Manhattan Project, U.S. Army personnel wore badges made from discarded photographic film. Later models have colored level indicators, and are often built into ID or security badges.

A Geiger counter is the radiation detector most familiar to the average person, however. It measures the type (alpha, beta, or gamma) and level of radioactivity. Readings can give a user with Electronics Operation (Scientific) a clue as to the radiation’s source. For instance, atomic weapons contain uranium and plutonium, which are primarily alpha emitters.

A dosimeter is different from either. It tracks total exposure over a period of time and sounds an audible alarm if the dosage reaches dangerous levels. People working around radioactive materials are normally required to wear a dosimeter throughout their workday.

Geiger Counter (TL6). $800, 4 lbs., 4¥S/4 hrs. LC4.

Radiation Badge (TL7). This ID badge has a color strip indicator that shows the total dosage to which it has been exposed. $5, neg. LC4.

Geiger Counter (TL8). Has a digital display. $400, 0.5 lb., XS/10 hrs. LC4.

Personal Dosimeter (TL8). Industrial or military versions are the size of a pager, but the electronics can be miniaturized to fit inside a wristwatch (p. 31). $120, 0.5 lb., 2¥XS/yr. LC4.

From the start of the 20th century, there were attempts to locate targets via their acoustic emissions. During WWI, sound detectors successfully triangulated firing enemy artillery this way. Sound-detection equipment is available after 1910 in any industrialized nation.

A sound detector gives +4 to Electronics Operation (Sensors) rolls made to analyze and identify a particular sound. It can also zero in on and magnify sounds from a particular distant point for eavesdropping; this requires an Aim maneuver. Sound detectors work only in air – not underwater (use hydrophones, see above, which are far more sensitive) or in vacuum.

Sound-Detection Gear (TL6). This sensitive array of horns can locate a sound source of 100 decibels (firing artillery piece, approaching aircraft, etc.) to within two yards at a distance of 10 miles. Apply +1 to skill per mile closer or 10 decibels louder, -1 per mile more distant or 10 decibels fainter. Ambient noise can give -1 to -10 (GM’s decision). Multiple observation sites are necessary to triangulate a target, and each site needs its own set of equipment. Triangulation requires either successful observations at three sites or a success at one and a critical success at another. $10,000, 400 lbs., external power. LC3.

Directional Microphone (TL7). A mike that picks up sound in a narrow cone similar in shape to a shotgun blast. Headphones included. Amplifies a particular sound by 4¥ at TL7, 8¥ at TL8. $800, 3 lbs., 4¥S/10 hrs. LC4.

Scientific researchers use a lot of specialized, expensive gear. Mad-scientist PCs can improvise to save money, but there can be consequences beyond simple skill penalties. Thomas Edison’s first “lab” was a loose collection of chemicals, batteries, and glassware in a freight car. An accidental fire ensured that the 15-year-old railroad employee was promptly evicted!

A portable lab provides the scientific equipment necessary to conduct research in the field, away from specialized analysis systems and major research facilities. It’s dedicated to a particular skill – Archaeology, Biology, Chemistry, Farming, Forensics, Geology, Metallurgy, Paleontology, Pharmacy, or any other scientific skill. The included instruments fulfill that skill’s equipment requirements when gathering and analyzing samples. If lab TL and skill TL don’t match, apply Tech-Level Modifiers (p. B168).

For example, a TL6 suitcase chemistry lab is a portable chemistry workshop. It lets anyone with Chemistry/TL6 analyze complex compounds, exotic alloys, etc. It can also manufacture chemical compounds (such as explosives) in small quantities.

Labs don’t get cheaper, lighter, or more effective as TL increases. They allow use of higher-TL skills and applications. At TL7-8, all labs require external power or a variety of batteries.

Suitcase Lab (TL5). A “mail-order chemistry lab” or equivalent. Takes at least 10 seconds to set up or pack. Counts as basic equipment for the skill. $3,000, 20 lbs. LC4.

Field Lab (TL5). Equipment similar to that found in a well-appointed high school or college lab. Takes at least a minute to set up or pack. Gives +1 (quality) to skill. $15,000, 200 lbs. LC4.

Mobile Lab (TL5). Enough equipment to fill a room. Takes at least 15 minutes to set up or pack. Gives +2 (quality) to skill. $75,000, 1 ton, external power. LC4.

Several items are useful not only for ordinary fieldwork but also for espionage, detective work, and other adventuring activities.

EM Field Meter (TL7). This device detects slight changes in electromagnetic (EM) fields. Scientists use it to test electronic equipment. Parapsychologists use it to detect the EM fields that purportedly accompany supernatural events. $500, 1 lb., S/10 hrs. LC4.

Fume Sponge (TL7). An absorbent tissue introduced into a target area to collect dust, smoke, chemical droplets, etc., for later analysis. To analyze the materials on the sponge, roll against Chemistry or Forensics. Success may confirm the presence of a top-secret weapons factory, invisible pollution, or even a particular person (from his chemical “fingerprint” of toiletries, hair particles, body odor, etc.). $50, 0.5 lb. LC4.

Metal Detector (TL7). This is a handheld detector about a yard long. The user wears the attached headphones and sweeps the ground in front of him as he walks. If he finds something metallic, the device will beep. A basic model – often used as a mine detector – can detect metal up to 20” underground, although 6” is more typical for small objects like coins and rings. Higher-quality equipment can detect large objects much deeper, and at TL8 has a screen that displays the general shape and composition of the find. Halve weight at TL8. $100, 12 lbs., 6¥S/8 hrs. LC4.

Dart Transmitter (TL8). This is a radio beacon in a standard 11mm dart (p. 89). Use a radio direction finder (pp. 38- 39) to track it. The internal battery lasts for 3 days. $200, neg. LC4.

Pocket Weather Station (TL8). This cell phone-sized device has a large display screen and a coin-sized wind turbine, and displays altitude, barometric pressure, wind speed, temperature, wind chill, relative humidity, and dew point. The internal rechargeable battery lasts for 15 hours of continuous monitoring or hundreds of “spot” readings. $300, 0.5 lb. LC4.

TDS Tester (TL8). A pen-sized gadget that can detect the total dissolved solids (TDS) level in water, indicating whether water is safe to drink. $20, neg., T/1,000 hrs. LC4.

Temperature Gun (TL8). A non-contact infrared sensor for reading the surface temperature of objects up to 12 yards away. Beyond its scientific and engineering uses, ghost hunters claim it can detect “cold spots” generated by some supernatural phenomena. $400, 0.5 lb., S/20 hrs. LC4.