VEVOR Step Drill Bit Set, 3.2 - 22.2 mm, 3 Pieces Step Drill Bits, 6.35 mm Hex Shank, TiAlN Coating Cobalt HSS High Speed Steel, for Metal, Stainless Steel, Aluminum, Wood, Plastic, FiberglassProduct Features Professional 3 Piece Set The step drill bit set includes a 13 step bit(1 8 1 2 in) for electronic enclosures, a 9 step bit(1 4 3 4 in) for mechanical assembly, and a 12 step bit (3 16 7 8 in) for mixed ranges, meeting diverse drilling needs Long Lasting Sharpness The step bit set is made of cobalt high speed steel with an AlTiN coating to withstand wear and stay sharp. It is ideal for stainless steel, metal sheets, and other tough