... T613.2-96 D6~D40 Hss Step drills from 4-39 mm. Coated with a TIN coating that ... size:Sizes: 4-12 mm step: 4, 6, 8, 10, 12 mm 40-20 mm step: 4, 6, 8, 10, 12, 14, 16 ... , 24.5, 28 mm 40-30 mm step: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, ... 26, 28, 30 mm 4-39 mm step: 4, 6, 9, 12, 15, 18, 21, 24, 27, 30, ... , Cobalt Coated, TiALN Coated All shank with 1/4" quick change hex shank or 3/8" quick change ...