The dog tag is an oblong piece of metal used for identification by military forces. Embossed upon the US dog tag are the wearer's name, rank, branch of service, social security number, blood type, and religion*.

Dog tags are issued in pairs, on two chains. The primary chain is of a size to put around the neck, the secondary chain is a mere 4 inches long. The second dogtag is normally threaded onto the laces of the wearer's combat boots (suitably muffled if need be). If the wearer is dismembered, or their torso destroyed, the second dog tag will hopefully survive enough to identify the corpse.

*Many non-Christian (especially Jewish) members of the US military will have NO PREF listed as a religion, especially when stationed in the Middle East.