The Bosch 2608595422 SelfCut Hex Shank Extension delivers extended reach when drilling The Bosch 2608595422 is a 1/4-inch Hex-Shank Extension for Self-Cut Speed spade bits which delivers extended reach when drilling. This extension is ideal for all applications with spade bits where extra length is needed. It has a 1/4-inch hex shank, and is intended for use with drill drivers. Features: Two different extension lengths available at 152 mm and 305 mm Ideal for all applications with spade bits where extra length is needed 1/4-inch Hex-Shank Extension for Self-Cut Speed spade bits delivers extended reach when drilling Specification: Length: 152mm Shank: 1/4 Inch