The third version of the USMC M1955 body armor was made of nylon and had rifle guards on both shoulders. The vest had a ¾ collar made of six piles of ballistic nylon and contained 23 doron inserts in overlapping pockets below the shoulder area.11.Personnel Armor Handbook by LT R. A. Green, J. A. Parish (U.S. Naval Weapon Laboratory June 1971)