The woodworking drill bit is HSS 4241, the center chamfer drill body is NO. 45 single steel spline edge chamfer 90 degree 7 sizes in one drill bit set (3mm/4mm/5mm/6mm/7mm/8mm/10mm), which meet your different needs perfectly. A set to send a small wrench, countersunk head diameter can be drilled in depth and control Drilling length can be adjusted for different length screws by simply loosening and tightening the set screws. Chamfer is 5 flutes which can discharge wood faster in the process of using, smooth drilled disposable sink hole, perfect screw cap embedded in the workpiece surface Use on steel, aluminum and other metals, wood (hardness less than 25 degrees) and plastic, ideal for production, maintenance or portable drilling jobs. Our products are made with the highest quality materials and are designed to provide you with the best possible user experience. We strive to ship out all orders within three days of purchase, and the estimated delivery time is 8-63157 days. When shopping, please pay attention to the size and dimensions of the product to ensure that it meets your needs. In the title and , we have provided detailed information about the product, including its features and specifications We want you to be completely satisfied with your purchase, so if you have any questions or concerns, please dont hesitate to contact us. We are here to help and will do our best to assist you. Thank you for choosing our product. We hope you enjoy it