Grommet with Plain Washer #4 Brass 1/2" Black 12 Piece Set Made of heavy-gauge brass, assuring maximum strength and resistance against “pulling out.” Can be used interchangeably with plain or teeth washers. Meets Government Specifications, MIL-G-16491F, MS-20230, NASM-16491 and NASM-20230. Government Specifications Met: MIL-G-16491F, MS-20230, NASM-16491 and NASM-20230. Hole Size After Setting: 1/2 in.