The first metal “identity disc” was introduced in 1907. By 1913, Army ID tags were mandatory. By 1916, a second tag was added and by 1917 all combat troops had aluminum tags hanging from their necks by rope or chain. The information was stamped on the tags with tool and die.
The so-called “Navy/Marine” style tag was oblong, with uniform printing. With its rounded ends the M1940 rectangular stainless steel tag was introduced by the Army during WWII. Prior to 1959, the Marine Corps and Navy used a circular metal tag with stamped information. By 1959, all branches of the Armed Forces were using the now familiar stainless steel tag still being issued today.
With slight variations, the content of the embossed information remains the same: Last and First name, social security number, branch of service, blood type, and religious affiliation.
Plastic or rubber silences ensured that the tags didn’t clink together and give away the wearer’s location.