The Irwin auger wood drill bit has been designed for all general wood boring & offers a superior performance. The single spur cutting edge scribes the circumference of the hole for a smoother quality finish. The hexagon shank prevents slipping in a drill chuck or bit extension. The solid centre provides extra rigidity whilst boring, the self-feeding screw point provides faster boring in both soft & hard woods & the fully hardened body from tip to shank provides extra durability. The Irwin IRW10502766 Auger drill bit has the following dimensions: Drillbit diameter: 20.0mm Total length: 191mm Working Length: 126mm