Irwin took all the best features from the different types of wood bits and combined them into one drill bit. These Speedbors have spurs like brad points for clean holes, open flutes like Forstner bits for chip removal and self feed screws for fast cuts like auger bits. While primarily for carpentry and construction projects, woodworkers will appreciate their clean entry and exit holes on larger jobs. We recommend using a good quality corded drill as these bits exert quite a bit of torque force. Hex shanks prevent slippage even in keyless chucks. Overall length is 6-3/8" with maximum hole depth of about 5-1/2".