Order this Rock-On #9 x 1-1/4 in. Rock-On Serrated Flat Head Star Drive Cement Board Screws for delivery. Serrated head design for flush seating even at an angle. Star drive with T-25 bit provides Stikfit for easy 1-handed installation and eliminates cam-outs. Patented sharp point offers immediate pick-up and eliminates the need to pre-drill. Serrated thread forms require less torque for faster installation. Patented design allows attaching close to edge on cement board, reducing fractures or blow outs. Premium corrosion resistant finish. Use to attach cement board to wood or light gauge steel studs. Conforms to ANSI A108.11 standards for cement board attachment.