21 piece, black oxide, metal, drill bit set, set consists of: (2) 1/16, (2) 5/64, 3/32, 7/64, (2) 1/8, 9/64, 5/32, 11/64, (2) 3/16, 13/64, (1) 7/32, 15/64, (2) 1/4, 5/16, 3/8 & 1/2 drill bits, no skate tip for clean & accurate starts, black oxide coating generates less friction, three-flat shank promotes better grip on bits 3/16 & larger, universal drilling applications designed for general purpose use, high visibility marking provide clearly marked diameter.