Kreg Jig Heavy Duty Replacement Drill Bit From the manufacturer: Make specifically for Kreg Joinery and exclusive use with the Kreg Jig HD Features a  hex shank and compatibility with our Quick Change Chuck Drills a HD 1/2 diameter Pocket-Hole Features hex shank for compatibility with standard and quick-change chucks Hex shank provides improved drilling torque, prevents chuck slippage Package includes drill bit, stop collar and allen wrench