Pozisquare® driving recess allows high driving torque and "stick fit" between driver and screw Made from hardened steel, zinc plated and yellow passivated with a waxed finish Ribbed countersunk head Fatter neck and thicker shank allow for a deeper recess and improved wall plug performance Drills own pilot hole even in hardwoods, and reduces splitting Single-start thread for better holding power and stripping resistance Driver bit supplied with each box of screws