Vault 13 Canteen

"You take a sip from your trusty Vault 13 canteen."

 is a miscellaneous item in Fallout: New Vegas which frequently fails to load into the player's inventory being based on the item being downloadable content.

Characteristics
The canteen essentially stores an infinite source of water, automatically lowering the player's H2O meter on a regular basis, and is useful primarily to ward off dehydration in hardcore mode, as well as restore a very small amount of health (15) even in casual mode. The canteen can thus help with the Achievement/Trophy "Hardcore", though the Vault 13 canteen only provides supplemental amounts and will not serve as a sole water source, requiring regular water resources such as purified water or dirty water to keep the player hydrated.

In both hardcore and casual mode, as long as the canteen is in the player's inventory, the player will periodically receive a message at the top left corner, "You take a sip from your trusty Vault 13 canteen", and the H2O meter will drop by 25. Since H2O is not important in casual/non-hardcore mode, this may become more annoying for some people than useful.

A five minutes timer triggers the player's drink and subsequent notification. This timer seems to start at the very beginning of the game start, not when a saved game is loaded and runs in the background even when the pipboy is up. However, under certain circumstances - such as sleeping or fast travelling right before the hydration level reaches the trigger point - the player can "jump past" the trigger point and become dehydrated.

Location
The Vault 13 Canteen is acquired exclusively from the Classic Pack.