3 Piece, Countersink Set, Rapid Load System, Durable Rubber Finger Grips For Comfortable Use, Impact & Rust Resistant Nickel Plated Nose, Stainless Steel Interior Parts & Pressure Activated Ball Groove System For Rapid Loading & Strong Retention, Provides Quick & Easy Accessory Changes Without Rechucking, Accessories Have Hex Shank Locking System To Prevent Slipping, Holder Fits All Brands Of 3/8″ & 1/2″ Cordless & Corded Drills.