The armored Vault jumpsuit is a modified version of the regular Vault-TecVault suit, modified to better protect its owner in combat. While it has the name armored Vault jumpsuit, it appears as a normal Vault jumpsuit with several plates, most likely from leather armor, attached to provide additional protection. Both the armored Vault jumpsuit and leather armor share similar textures and the distinctive single shoulder guard, a tribute to the acclaimed Mad Max series that featured similar, distinctive armor. This suggests that Vault 101's Vault experiment that "no one ever enters and no one ever leaves" was not quite successful.
The suit can be found in Craterside Supply, Moira's store in Megaton. Moira bestows this gift on the player after complying with a request to recall how life in Vault 101 was. Moira explains that she made this suit for a girl from the Vault around "10 or 12 years ago," but the girl never returned to pick it up, leading Moira to speculate that she may have died.
The way the suit is displayed in Moira's store is somewhat similar to the way you find The Vault Dweller's suit enshrined during Fallout 2.
If stolen you will receive no Karma penalty.
The suit appears to change color depending on its condition.
The suit seems to be considered the Fallout 3 promotional armor set, because it appears on the character in all ending cutscenes.
The vault boy icon for this piece of apparel portrays the vault boy with his back turned, similar to how the Lone Wanderer is portrayed at the end of the main storyline while wearing this same piece of apparel.