HSS4241 High Speed Steel Step Drill Bit 10-45 Spiral Step Drill Bits, Nitrogen Coated Made from high speed steel and nitrogen coated to reduce friction and run cooler. < li>Spiral cutting flute; automatic deburring of holes when you drill. Application: suitable for parts less than 25mm hardness, such as carbon steel, sheet metal, insulation boards, PVC panels, planks and wood with a thickness of less than 5 mm. 8 levels: 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45mm. Features: Color: Black (as picture). Material: 4241 high speed steel. Surface: nitrogen treatment (increasing hardness and abrasion resistance). Stem: triangular round handle. Type: 10-45 mm Total dimensions: 45 x 100 mm. Weight: 350 g. Contents: 1 step drill bit 10-45.