UAC credits

UAC credits are only found in Doom RPG and Doom II RPG and they are used in vending machines found in the game. They are either silver or gold in color, with the silver ones valued at one credit and the gold ones being five credits. They can be used to buy medikits, ammo and upgrade the marine's stats.

They are also mentioned by the Doom 3 UAC announcer at the start of the game. They are also seen in lifts in doom 3 Explaining that if you want more UAC Credits you should become a security guard.