Constructed of M-35 5 percent cobalt high speed steel for super abrasive resistance in tough metals. Cobalt steel extends cutting edge life and maintains cutting life after resharpening. Extra hard drill for greater wear. 135° 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 overmolded case protects kit if dropped. Tap & Drill selection chart for convenient reference. Automatic indexing for easy bit access and identification. Removable cartridges: easy to carry bits from case to worksite. Sizes include 1/16″ to 1/2″ in 1/64 increments. Add to Favorite Sellers. AHN 3018002 29 Pc. Cobalt M-35 Metal Index Drill Bit Set.