Stamped on reverse: "POISON INSIDE". Two eyelets on body for tie string (does not come with any string). In advance of the D-DAY Invasion on June 6th, 1944, luminous discs where issued to American Paratroopers so they could be identified easily by friendly troops. Typically fixed to the back of the M1 helmet by fastening to the helmet net, clipped or tied onto webbing or stitched onto the inside of the M42 jump jacket collar at the back so the wearer could pull his collar up to reveal the luminous disc.
Designed to be used when moving at night so the soldier could keep an eye ...