【DRILL SIZE】times; (4-12mm), 1 times; (4-20mm), 1 times; (4-32mm) Step Drill Bit. Step drills have three sizes to meet your needs. your different needs. And the package contained a nylon bag. 【DOUBLE CUTTING BLADES】: Double cutting blades and X-type opening design ensure faster and smoother cutting; 3-sided shank design can prevent the chuck from slipping; With the slightest pressure, the clearances can be cut to the right size. through wood, sheet metal, steel and other surfaces. 【HEX SHARK】1/4" (6.35mm) hex shank works with most drills or drills with a 1/4" chuck, fits securely into the power tool chuck and eliminates slippage. 【HSS & TITANIUM COATING】Made of super strong HSS steel and coated with titanium, titanium coating ensures easy cutting of steel, aluminum sheet, brass, copper, plastic, wood, etc. 【APPLICATION】Suitable for sheet metal, sink, auto repair, etc. Widely used for drilling holes in a variety of materials such as plate, aluminum, insulation board, PVC board, wood