Based on the Armour Model 50, which was developed by Marvin Camras in 1942 and used by the military in World War II. Pierce was one of many manufacturers that licensed technology from the Armour Research Foundation during and after the war. For several years Armour was able to support their wire recorder research through licensing.

Reels could hold ½ hour or 1 hour of audio with speeds of 5 or 2½ ft. per sec. The wire is a ferromagnetic alloy of stainless steel.