This experimental radio helmet was used by the United States military during the late 1950s and into the Vietnam War. It is made of plastic material similar to M-1 liners and had all types of communication equipment installed (batteries, transmitter, microphones, earphones).1 The interior suspension resembles that of a parachutist liner. The nomenclature inside the helmet dates it to 1956.
Radio Corporation of America (RCA)
1 Chris Armold, Steel Pots: The History of America’s Steel Combat Helmets (San Jose, CA: R. James Bender Publishing, 1997), 209.