Designed for attaching HardieBacker or equivalent fiber cement backerboard to wood or light gauge steel studs BackerOn’s patented serrated head design countersinks for flush seating at any angle, providing a smooth surface for tile Star drive recess with T25 bit provides for onehanded installation Climacoat corrosion resistant finish prevents rust from bleeding into grout and are perfect for use in high moisture areas Conforms to ANSI A10811 for cement board attachment