Vault Jumpsuit

The Vault Jumpsuit is a set of standard clothing worn by all inhabitants of Vault-Tec Vaults. Vault suits from Fallout and Fallout 2 were depicted as skin tight, but they were not so in Fallout 3. Thus is likely just a difference of design interpretation, though some speculate that the Vault suits in the Capital Wasteland were just made differently in-universe.

A variant of this suit, modified for extra protection, is called the Armored Vault Suit.

Appearances
Vault Jumpsuits appear in all Fallout games. However, in Fallout and Fallout 2 they are worn by the player character by default and only in Fallout 3 appear as actual in-game items.