Original issue, US Army Technical Manual,  11 pages, size is 8 1/2" x 11", stapled, dated 15 June 1987.  This is not a commercial copy or print but an original issue government print issued in 1987 and republished in 1990 to include changes 1 through 3.  This publication is titled - TM 55-1680-322-12, Operation and Service, Distress Marker Light, SDU-5/E.  Publication is designed to provide information and instructions on the operation and maintenance of this aircrew survival light.  Very well illustrated using clear and detailed line drawings.