The emergency signaling mirror is intended to reflect sunlight at passing ships, aircrafts, or rescue parties. Instructions for using the mirrors are printed on the back of the mirror. There is a hole in the corner of the mirror through which a lanyard shall pass so the mirror may be looped around the neck.

2" x 3" Signal Mirror Applicable reference documents:
MIL-M-18371, Type I
NSN: 6350-01-455-6695