Package Included - 1*4-12mm Metal Step Drill Bit, 1*4-20mm Metal Step Drill Bit, 1*4-32mm Metal Step Drill Bit. HSS 4241 Titanium Coated - Made of HSS 4241 steel, coated with titanium Profi Hex Shank - Size: 4-12mm Length: 6.9cm; Size: 4-20mm Length: 7.3cm; Size: 4-32 mm Length: 10.3 cm Extra Long Life - Pour water while working with the step drill bit to effectively extend the life A Variety of Materials - Perfect for home improvement and general construction supervision; For cutting holes in a variety of of materials, including stainless steel, wood, thin iron/copper, aluminum, PVC, wood, plastic, etc. Spiral Groove Design X-type opening design for easy removal of cutting waste when drilling Self-Centering The 118 X-shaped opening design prevents the drill bit from slipping during drilling A Variety of Materials A variety of materials, including stainless steel, wood, thin iron/copper, aluminum, PVC, wood, plastic, etc. Self-Centering The 118 X-shaped opening design prevents the drill bit from slipping during drilling. 118 prevents the bit from slipping while drilling Universal Handle Sturdy and Durable 1/4" (6.35 mm) Hex Shank works with most drill bits or bits with 1/4" chuck Double Spiral Groove Reduces cutting resistance and faster chip removal The spiral groove design at Two flutes allows for faster, more stable and smoother cutting, automatically deburr holes when drilling Specification: Color: Golden (as picture shown) Material: High Speed Steel Surface: Titanium Coated Scope: Thin iron plate, aluminum, insulation boards, PVC boards 4mm thickness in wood. Package Included: 1 x Groove Drill Bit 4-12mm Spiral Drill Bit 1 x 4-20mm Spiral Grooved Drill Bit 1 x 4-32mm Spiral Grooved Drill Bit