Features:* * Made of hss-co, heat treatment, high hardness, high wear resistance, high strength, high bending strength, sharp edge, the best choice for stainless steel processing, better than ordinary step drill bit.* To reduce the myth and run cooler.* Automatically removes holes when drilling.* Unique step structure, drill bit that allows you to make holes of different sizes, making the perfect hole easy.* Step drill bit with box. Very convenient.* It doesn't need a punch center to help it, compared with ordinary hemp flower drill, it is stabler and difficult to break.* Suitable for mounting on pistol drill and bench drill, suitable for punching on harder objects, widely used for cutting holes in various materials, such as stainless steel, wood, thin iron, aluminum alloy, moisture plate, pvc sheet, ectNote: It should be water to cool when punching, so that it can prolong its service life, rotation rate from 250 to 400 is recommended. Specifications:Material: hss-co (HSS M35 5% Cobalt)Handle Type: Hexagonal Handle Diameter: 1/4" (6.35mm)Model Step Quantity Edge Length Handle Length Step Diameter 3-12mm 9 Steps 50mm 31mm 3-4-5-6-7-8-9-10-12mm4-22mm 10 Steps 50mm 31mm 4-6-8-10-12-14-16-18-20-22mm6-24mm 11 Steps 57mm 31mm 6-8-10-12-13-14-16-18-20-22-24mm Package Content:3*Drill Bits