Grommet with Plain Washer #4 Brass 1/2" 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. Questions? Send us an e-mail here on Amazon. We respond to all e-mails within 24 hours and usually much faster. Northwest Tarp & Canvas - Bellingham, Washington