Vault Jumpsuit

The Vault Jumpsuit is a set of standard clothing worn by all inhabitants of Vault-Tec Vaults. The exact design of the suit is the same within a vault, but it seems that Vault-Tec might have purchased them from different subcontractors in different regions - e.g. the Vault Suits used in California Vaults, like Vault 13 or Vault 8 are skin-tight, while the ones from Vault 101, Vault 106 and Vault 112, located near Washington, DC, are more baggy.

While it's possible that differences in materials led to the baggy appearance of the Eastern Vault Suits, a more reasonable supposition is that the appearance of the Vault-Suits in Fallout 3 is simply a difference of design interpretation and a retcon. Thus, Vault Suits were always baggy.

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.