(Product Specifications) Material: High-speed steel, titanium coated surface; Size 1: 0.1 - 0.5 inches (3 - 12 mm), 10 steps (length 2.7 inches (69 mm), Size 2: 0.1 - 0.5 inches (4 - 20 mm), 9 steps (Length 3.3 inches (83 mm), Storage bag size: Approx. 4.3 inches (12 mm) Weight: Approx. 3 lbs (12 mm) for use with impact driver, electric drill. Package Includes: 1 x Step drill (3-12mm) 1 x Step drill (4-12mm) 1 x Step drill (4-20mm) 1 x Storage pouch *The color and size of the actual product may differ slightly from the images on the website depending on the lighting and your display. If you have any defects or concerns on the product, please do not hesitate to contact us (^_^). Product Description: Adopts high speed steel 4241: Our step drill uses super high hardness high speed steel (HSS steel 4241), and the surface is coated with titanium to make it harder and sharper than ordinary steel step drills. High speed steel is a tool material that can be used to make cutting metal materials at a higher temperature as it is used after heat-tempering process, such as tempering, and then sanded to compensate for low softening resistance at high temperatures. The step drill enlarges the holes in order from small to large holes to allow for multiple sizes and enlargement of holes. The shape of the shaft is hexagonal shaft, so it can be used with impact drivers. Applicable Scenes:The step drill extends the holes in order from small holes to large holes, so you can modify multiple sizes of drilling and enlarging holes. The shape of the shaft is hexagonal shaft, so it can be used with impact drivers. Wide range of uses: An essential tool for drilling stainless steel, thin iron plates, aluminum plates, wood, vinyl, resin, etc., for household DIY, enlarging the lower hole, chamfering, deburring, etc. A must-have item for home & work. [Caution] Heat generates when using the drill, so it may cause burns if touched with bare hands. Be sure to wear protective glasses, safety gloves and masks while working. Please follow the proper rotation speed. Always use cutting oil when processing stainless steel. Please refrain from drilling that exceeds usage conditions as this may lead to product damage. Please do not force the drill by forcefully pressing or swinging it left or right. In order to prevent injury, we recommend fixing the cutting object with tools before work. Please avoid overloading when using a charging impact screwdriver, as there is a risk of breaking the shaft or breaking the edge.