These Sheffield Masonry Drill Bits feature the Spline Drive System and are for direct mounting into Black & Decker, AEG, Bosch, Dewalt, Hitachi and all hammer drills with spline shank drives. Spline drill bits deliver maximum drilling torque and energy per hammer blow for faster drilling and the least cost per hole drilled. Sheffield EVO Tips are standard on all of our bits. The small particle size that Sheffield uses in their tungsten steel makes the Evo Tip the strongest most durable on the market. The design of the tip is also a contributing factor to the tip's durability. Sheffield Masonry Drill Bits are made from the world's finest carbide and steel. Brazing techniques are used to produce the most durable and lasting bond. This bond ensures an extended drill bit life. The double flute design allows debris to flow down the flute in two paths - one from each side of the cutting head. The more debris removed, the faster the bit can drill.