Stealth Boy

RobCo Stealth Boy 3001 is a personal stealth device worn on one's wrist. It generates a modulating field that transmits the reflected light from one side of an object to the other, making a person much harder to notice (but not completely invisible).

The technology was developed by Robert Mayflower, based on captured Chinese Hei Gui stealth armor units, belonging to the Black Ghost counterinsurgency/terror units.

After the war, it was used by the Nightkin elite super mutant units of the Master's army.

Fallout
Nightkin NPCs can be seen using Stealth Boy, however, their usage is entirely cosmetic. Unlike the mechanics of traps, the player does not have to make a saving throw in order to spot Nightkins.

Side effects
Some time after they acquired the Stealth Boy technology, the Brotherhood of Steel experimented with those devices. It turned out that prolonged use causes the user to suffer paranoia, delusions, and eventual schizophrenia. When this was discovered, the devices were banned and the team disbanded. However, it was not known that the team had already begun to suffer the effects of the device. Thinking the disbanding of their team to be a conspiracy, they decided to steal the Stealth Boys and form a new covert operation called the Circle of Steel.

Locations
Fallout:
 * Giant Footprint special encounter - on the body of a dead peasant
 * The Glow Level 5 - in a locker
 * Cathedral Tower (All Floors) - on Nightkin Sentries
 * Cathedral Lair Level 3 - in a locker

Fallout 3:
 * Farragut West Metro Station - In an office
 * Tepid Sewers when you first enter to subway. Deal with 3 raiders (1 behind sandbags, other 2 in corridor); enter the corridor, go ahead to the main room. The Stealth Boy will be in the floor safe between 2 beds.
 * Museum of Technology on display. One in the atrium, two more on the upper level.
 * Minefield in one of the house safes.
 * Canterbury Tunnels toward AntAgonizer's Lair, on a shelf near a mined hallway.
 * Broken Bow In Pinkerton's workshop there are two of them (Broken bow is the broken off part of the Rivet City boat).
 * VLPL-84 Power Station north of Robco Facility and Tenpenny Tower in a truck.
 * National Archives sub-basement in the generator room behind a Very Hard locked gate.
 * Germantown Police HQ On the upper level, inside a safe in a corner.
 * Robco Facility At least four, scattered around the place.
 * Museum of American History Ahzrukhal's safe in The Ninth Circle in Underworld
 * Vault 106 Crazy doctor uses one when he attacks you.
 * VAPL-58 Power Station inside in the back on the control panels.
 * Northwest Seneca Station In grocer within the safe.
 * Super-Duper Mart In northeast corner of the store behind the counter.
 * Megaton Inside the armory.
 * Vault 108 Entrance on a table next to a broken computer.
 * Gallo Under an overturned crate in his storage closet.
 * Bethesda Ruins West, one on the lower floor, in a crate next to the water fountain, another upstairs on the table.
 * Bethesda Underworks in a skeleton's hand in the central storage room.
 * Vault 92 Overseer's Office, sitting in the center of the desk.
 * Vault 101 after returning, inside the entrance, on the body of Steve Armstrong.
 * La Maison Beauregard at Georgetown East, upstairs on the pool table.
 * Georgetown, NE of the DCTA Tunnel 014-B Potomac, upstairs of a building housing Super Mutants.
 * In one of the Abandoned Shacks buildings, just north of Jalbert Brothers Waste Disposal and east of Rockbreaker's Last Gas, on the table.
 * Statesman Hotel, in a safe at the counter after you rescue Reilly's Rangers
 * Dupont Station in the middle of the three abandoned houses guarded by raiders. It is located on the floor next to the shelf case.
 * Robot Repair Center in an ammo box on a counter in the conveyor belt room.
 * Abandoned Shack on cliff west of Rockbreaker's Last Gas. It is in a hole in the first locker.
 * Megaton in Billy Creel's House in the floor safe.

Appearances
Stealth Boy can be found in the first Fallout and Fallout 3, although it is mentioned in Fallout 2 and its description is present in Fallout Tactics files. The device's back story wasn't developed until Van Buren, the canceled Fallout 3 by Black Isle, where it was spelled as StealthBoy to prevent it from being confused with the "Stealth Boy" playing style.