This drill bit has a precision ground 82 tip for countersinking most machinable metals, wood or plastic. It is made from industrial grade high speed steel for increased durability and includes a black oxide finish for added corrosion resistance. It features a five flute design reduces vibration for smoother drilling and extended life and its 1/4 In. round shank fits all handheld and stationary drills. Set includes: 1/4 In., 3/8 In., 1/2 In., 5/8 In. and 3/4 In.