3M Wetordry coated 431Q sand paper sheet uses silicon carbide as the abrasive material. 3M incorporates this silicon carbide material into the sand paper sheet forming a grit of 180. The sand paper sheet has a width of 9 in and length of 11 in. This abrasive is on a paper backing, C weight. The National Stock Number (NSN) for this part is 5350-01-516-9015.