Blondie's dog tags

 are a miscellaneous item in Fallout 2.

Characteristics
Collecting all three dog tags from the merc captains and using the combination of numbers etched on the back of them on the safe will allow it to open without setting off the trap.

Location
can be acquired from Blondie's locker, located in the Mercenaries' cave between Broken Hills and Vault City.

Behind the Scenes
This item is a reference to the character in "The Good, the Bad and the ugly", played by Clint Eastwood.