The unique Rota Stop shank guarantees a positive lock in the chuck or extension bar and a quick release. This feature is also included on the shanks for the Colt Extensions. The cutting edges are diamond ground from the highest quality raw material to give the sharpest edge and the cleanest holes. The periphery of the hole is precut before the main cutters commence work which prevents splintering. The main cutters are sectional to create smaller shavings which permits a higher drill feed speed and faster work. Suitable for end grain and side grain. All bits are 10mm shank. Made in Germany.