Efficient and precise to drill, no additional edge cleaning required. Tungsten carbide tip and heat resistant coating for long lasting performance, sharp and durable, precision balanced for operation gently. Is designed to fight hinges, trim and plywood puncture, as well as plastic products. Specifications: 15mm, 20mm, 25mm, 30mm, 35mm one piece each. Packing Details: OPP self - packed in a bag. Wooden box. Suitable tools: drill electric with clamp greater than or equal to 10mm, table drill, high-power electric grinder, pneumatic drill, magnetic drill, gun drill. Scope: This series of products can do the exquisite punching you need on all kinds of wooden boards, wooden products, plastics, splints and other materials, suitable for installing industrial hinges, repairing woodworking, model making, installation of spherical door spikes, drawer spikes and other occasions < p> Performance Benefits: 1. Made with advanced process, high quality material, solid and durable. 2, the open hole is clean, smooth, no broken edge, will not produce tremor phenomenon. 3, the cutting resistance is small, the hole opening speed is improved, the chip evacuation is easy.< /p> 4, can be used for all kinds of wood panels, wood products, plastic, Splints and other open hole materials. 5, simple installation and easy to use, just install on a normal hand-held electric drill to use. 6, small working noise. Note: The data are all measurements manual, please allow 1 - 3cm error, due to the difference in light and display, there will be some color difference, depending on the physical object received.