Features Premium Quality: These step drill bits are made of super strong metal and titaniums coated, the titaniums coating ensures easy cutting of steel, aluminum sheet, brass, copper, plastic , wood and many other kinds of metal. Various Sizes: This step drill bit set has 3 kinds of sizes, the dimensions-of the steps cutter for metal are: 4–12 mm, 4– 20mm, 4-32mm, can meet your needs in different situations Application: Widely used for cutting holes in a variety of materials such as plate, aluminum, panel insulation, PVC panels, wood thickness is less than 5mm. Package Content: 1 x 4-12mm, 1 x 4-20mm, 1 x 4 -32mm. Application: Suitable for punch holes through sheet metal, iron plate, aluminum plate, brass, wood, plastic, etc. .Notice: Actual color may be slightly different from the image due to different light effect Please allow 1-3cm deviation due to manual measurement Description: Material: Silicone Size: 3.75x3.75inches Package List: 3pcs 4‑12/20/32mm Drill Cone Bits