Specially designed screws for attaching Durock cement board to wood framing. Corrosion-resistant and has wafer heads with ribs to prevent strip out. 1-1/4" long screws are used for applying 5/16" Durock underlayment or 1/4", 1/2", and 5/8" Durock cement board to subfloors and countertops or 1/4" and 1/2" Durock cement board to walls. 200 screws per package.