Keyring

The keyring is a miscellaneous item in Fallout 3 and Fallout: New Vegas.

Characteristics
Selecting it in the Pip-Boy allows the player to see all of the individual keys the player has found, received, and stolen. This includes physical keys, key cards, access codes, VIP cards, and recorded audio passwords—any item that the player uses to access a locked door or container.

Locations
It appears in the Pip-Boy inventory under the "Misc" heading.