Oxide treatment resists corrosion, helps prevent bit from rusting. 135 degree split point tip starts on contact, cuts with less force. Reduced shank above 3/8" allows the use of larger drill bits in a 3/8" chuck. Rubber over molded case protects if dropped. Tap and Die selection chart for convenient reference Automatic indexing for easy bit access and identification. Removable cartridges: easy to carry bits from case to worksite. Set contains the following drill bit sizes: 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32", 11/64", 3/16", 13/64", 7/32", 15/16", 1/4", 17/64", 9/32", 19/64", 5/16", 21/64", 11/32", 23/64", 3/8", 25/64", 13/32", 27/64", 7/16", 29/64", 15/32", 31/64", 1/2".