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The Vault - Fallout Wiki
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This is a lore summary, presenting intradiegetic or in-universe information about the subject. For game characteristics and similar data, consult the table on the right.
Game-specific articles
FalloutStealth Boy
Fallout 3Stealth Boy
FO: New VegasStealth Boy
Stealth Boy mark II prototype
Fallout 4Stealth Boy
Fallout 76Stealth Boy
Stealth Boy Mark III
Van BurenStealth Boy
Fallout: BoS 2Stealth Girl

The RobCo Industries Stealth Boy 3001 is a personal stealth device.


One of the most interesting technologies developed before the war, the Stealth Boy 3001 is a wrist-mounted device that generates a modulating field that transmits the reflected light from one side of an object to another (called stealth radiation[1]). The end result is practical invisibility, which can range from translucency to near-perfect active camouflage.[2][3]

The underlying principle of bending light to create invisibility wasn't invented by the Americans. Robert Mayflower, the man responsible for creating Stealth Boys under RobCo's aegis, reverse-engineered captured Chinese Hēi Guǐ stealth armor.[4] The technology wasn't perfect, but proven itself reliable enough for military purposes. In fact, it was enough to convince the military to have had these devices mass produced.[5] Even more, work started on a more advanced Stealth Boy mark II prototype.[6] After the Great War, developed by Enclave scientists in Appalachia, the Stealth Boy Mark III was an overall improvement of the Stealth Boy, coming at the cost of reverting back to a specialized canvas holder design rather than a wrist-mounted design.

There are drawbacks to the Stealth Boy, however. Apart from limited battery life, particularly when used at full power to achieve total invisibility, the modulating field can cause permanent neurochemical changes,[7] resulting in the development of mental conditions, such as paranoia, delusions, hallucinations, and even schizophrenia.[8] This is by far most noticeable among the nightkin, former elite members of the Unity and their prolonged Stealth Boy use and apparent increased susceptibility of super mutant physiology to stealth radiation. Nightkin tend to suffer from delusions, anxiety attacks (particularly when deprived of their Stealth Boys), and heightened aggression (particularly when trying to acquire Stealth Boys to cope with their withdrawal symptoms). Treatment is difficult and usually focuses on symptoms, due to the inability to address the underlying cause (yet).[9][10]


Stealth Boy Mark I (Canvas Box)

StealthBoy01 20151205 19-10-45.png
Gameplay article:

The first generation of the Stealth Boy. This variant of the Mark I Stealth Boy was bulky and needed to be encased in a canvas waist pouch to be actively used. Later models would miniaturize and wrist mount their devices for more convenience.

Stealth Boy Mark I


The Stealth Boy 3001 is the most common variant of active camouflage devices in the wastelands. Lightweight, wrist-mounted, and portable, they offer a number of power settings allowing anything from total invisibility to partial translucency.

Stealth Boy Mark II (Prototype)

Stealth Boy.png
Gameplay article:

The Stealth Boy Mark II prototype is an enhanced Stealth Boy, put through testing by the U.S. military shortly before the Great War. According to Doctor Henry, its purpose was to use less power and therefore last longer.

Stealth Boy Mark III

Stealth Boy mark III.png
Gameplay article:

Developed by Enclave scientists in Appalachia with the help of Chinese schematics and MODUS[11], the Stealth Boy Mark III was the total improvement of the Stealth Boy. While no longer wrist mounted (instead reverted back to a canvas box), the power consumption rate was drastically lowered from the Mark II Stealth Boys allowing for longer invisibility time until power was drained.

Behind the scenes

  • Although it is mentioned in Fallout 2 and its description is present in Fallout Tactics files. The device's backstory 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. Subsequent games incorporated much of the backstory into the mainstream canon.


  1. The Courier: "I found a chewed up Stealth Boy in the Nightstalker lair."
    Henry: "Hmmm... there's still power, but the casing is cracked. I'm astonished that exposure to the stealth radiation could induce mutations so rapidly. More importantly, this explains why my research into this group of Nightstalkers hasn't come up with a cure for the Nightkin. There's only one avenue left for me - I need to run the Mark II test on Lily. It's the only way."
    (Henry's dialogue)
  2. Fallout item description: "{5400}{}{Stealth Boy}"
    "{5401}{}{A RobCo Stealth Boy 3001 personal stealth device. Generates a modulating field that transmits the reflected light from one side of an object to the other.}"
  3. Museum of Technology placard: "This is the RobCo "Stealth Boy" Model 3001 Personal Stealth Device. Developed by Robert Mayflower, the Stealth Boy generates a modulating field that transmits the reflected light from one side of an object to the other making the bearer almost invisible to the untrained eye."
  4. Simple armor: "The Chinese solution to invasion by U.S. forces in power armor was its Hei Gui stealth armor, worn by elite Chinese "Black Ghost" counterinsurgency/terror units. Not much was known about this armor, save that it had active camouflage systems as well as technology that enhanced reflexes and heightened perception. Hei Gui technology was the basis for the unstable "Stealth Boy" wrist units developed in the U.S."
    Note: While Simple was never properly released, Hei Gui stealth suits are confirmed to have been reverse engineered by the U.S. at Big MT and elsewhere, while the adverse effects (for super mutants) of the Stealth Boy units were canonized by Fallout: New Vegas.
  5. Availability of Stealth Boys in Fallout 3 and New Vegas
  6. The Courier: "What are you working on?"
    Henry: "The Nightkin have varying degrees of mental instability due their addiction to Stealth Boy use. I've been trying to come up with a cure. I'm currently investigating the local Nightstalker population since they seem to have developed a natural stealth field. I've also gotten my hands on a working Stealth Boy Mark II prototype, but that experiment is riskier. I'd rather not pursue that research just yet."
    (Henry's dialogue
  7. The Courier: "What makes you think that the Nightstalker mutation isn't natural?"
    Henry: "I've compared the brain chemistry of a Nightkin to one of the local Nightstalkers we killed. They both exhibit similar neurochemical changes. Now, I'm not claiming that Nightstalkers are running around wearing Stealth Boys, mind you. I just don't think it's all a coincidence."
    (Henry's dialogue)
  8. The Courier: "What's wrong with the Nightkin?"
    Marcus: "Nightkin suffer schizophrenia from the Stealth Boys they're always using. One of the reasons I settled Jacobstown was so they could be cured. While they're in town, the Nightkin aren't allowed to have Stealth Boys so their craziness doesn't get worse. Trouble is the Nightkin don't like being visible, either. They don't take being exposed too well."
    (Marcus' dialogue)
  9. Jacobstown
  10. The Courier: "Why does Keene want to leave?"
    Marcus: "Because of a promise. One I haven't been able to keep. The Nightkin all suffer from schizophrenia. It's the Stealth Boys they use, used to use. Nightkin have a hard time being seen like normal folks. Can't stand it. A few already left to try and find more Stealth Boys. Miserable situation. They either stay here and suffer, or dig up Stealth Boys and lose their minds. Not much of a choice."
    (Marcus' dialogue)
  11. The Whitespring Bunker terminals#RE: Chinese Stealth Tech