Patented Phillips Square Driv Drive System * The Screw You"ve Used For Years Now Has A New Name! * ACR - Won"t Strip Out, Drives Off-Angle and Allows for More Torque * Lifetime Guarantee Will Not Rust - Can be used in Pressure Treated Lumber * Blue Driver Bit Included. Can use a #2 square and #2 phillips (ACR2 Phillips sold separately)