Are of general purpose flute design but all sizes have a 1/2 by 2-1/4 long shank. The maximum overall length is 6 and the flute length is 3. This makes them short drills in the larger sizes and thus well suited to use in portable electric drills equipped with 1/2 chucks. They are highly effective in tough, high tensile strength materials. The 135 degree split point reduces thrust and eliminates walking at the drill point.