Century Drill & Tool 47346 Economy S & D Drill Bits, 23/31 InchDesigned for drilling wood, soft metal and hard metal. Silver and Deming style drill bits with 118 degree split point. Highlights: Drill Size: 23 31 inch Reduced Shank: 1 2 inch Material: High Speed Steel Silver and deming style drill bits have a 135 degree point Surface treated to ward off heat and friction commonly found in heavy duty drilling jobs High speed black oxide finish, 2 tone Used to cut wood, soft and hard metals