[ materials, quality assurance] drill holders and cone drill bits are made of HSS stainless steel, durable. Operation suggestion: When using the electric drill, it should be as vertical as possible, do not shake or tilt, and the electric drill should not rotate too fast. Saving time and labor-saving, efficient and fast] HSS taper drill bit is made of high-speed steel, which can reduce heat and friction, cool quickly, and automatically remove debris in the hole when drilling. The spiral design can prevent slippage, making drilling easier and more efficient. Three sizes to meet your needs 4mm-12mm, 4mm-20mm, 4mm-32 mm, you can choose different drill bits according to your needs. A wide range of uses] The product can process thin iron plate, aluminum, insulation board, sheet metal PVC, wood panels and other materials with a thickness of not more than 3mm. Nylon fabric bag is convenient to carry The product is equipped with a nylon fabric bag nylon, which can achieve good storage and protection effect. There is no need to worry about the loss and wear caused by the small product. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.