The 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).
While they seem to not have any adverse effects on humans, Stealth Boys increase the risk of schizophrenia in nightkin, who, as permanent Stealth Boy users, nearly always show one or several symptoms of paranoid schizophrenia, such as paranoia, hallucinations, and/or delusion. Doctor Henry in Jacobstown is researching these side effects, hoping to develop a means to help the nightkin.
One can be found in the middle of Jack Rabbit Springs, beside a skeleton found lying near an upright post visible on the hillside.
Approaching the cattle pen at Brooks Tumbleweed Ranch reveals a nightkin who offers to sell you a 'wind brahmin' (a tumbleweed) for all your caps. Originally he will then give you a Stealth Boy as a gift; killing the nightkin afterwards (or pickpocketing him) produces another Stealth Boy, as well as all your caps back. But with the game patch released July 7–8, 2011, he will no longer give you a Stealth Boy and will take all of your caps instead, and you can only get one Stealth Boy from the nightkin by either killing or pickpocketing him.
Old World Blues (add-on) Passing the "Robot Compliance Test" to upgrade the stealth suit Mk II at the X-13 research facility may yield a Stealth Boy in the reward safe. This test and three others can be repeated and give random rewards each time, including Stealth Boys.
Old World Blues (add-on) In the nightstalker test area of the facility, shooting the forcefield in the ceiling of the small room with the Strange Still with an upgradedsonic emitter will drop a Stealth Boy into the room.
Old World Blues (add-on) In the Y-17 medical facility located near the Auto-Doc in the center of the room, it will be on the floor close to the rubble surrounding the Auto-Doc.
With Fallout: New Vegas patch 18.104.22.1684, Stealth Boys may randomly spawn in ammunition boxes.
Many can be found in the footlockers at Camp Golf.