Oxide treatment resists corrosion, helps prevent bit from rusting 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 .