BACKER ON 1-5/8 IN V60 CASE's patented serrated head design countersinks for flush seating at any angle, providing a smooth surface for tile. Stardrive recess with T-25 bit provides for one-handed installation. Climacoat corrosion resistant finish prevents rust from bleeding into grout and are perfect for use in high moisture areas. Conforms to ANSI A108.11 for cement board attachment.