Rock-On Cement Board Screws are designed for attaching Durock, Wonderboard or equivalent glass-mesh cement backerboard to wood or light gauge steel studs Rock-On's patented serrated head design countersinks for flush seating at any angle, providing a smooth surface for tile The Star drive recess with T-25 bit provides StikfitTM for one-handed installation Rock-On screws feature a Climacoat corrosion resistant finish that prevents rust from bleeding into grout and are perfect for use in high moisture areas such as baths, showers, countertops, and floors Conforms to ANSI A108.11 for cement board attachment. Rock-On screws can be installed with a standard impact or drill/driver and T-25 Star drive bit (included with product) for cement board fastening done right 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, drastically reducing fractures or blow outs.