Smooth Cutting Inserts::Tungsten carbide cutting tip with special heat treatment for sharp cutting edge, high hardness, non-burrs and durable use. Arc curve design head for easy chip-removal, more efficient perforation. 3PCS Different Drill Bits Set:Drill straight, angled and overlapping holes,size 16mm, 22mm, 35mm Drill Bit Round Shanks set X-Wing Design For Precision:X-wing head provides visibility and stability during operation. The center spur of each bit guarantees accurate drilling and prevents walking and wobbling during operation, create perfectly round and accurate holes with the center spur design. Application:Perfect used for drilling precision holes in all different types of wood, such as drawer, mounting spherical door shoot tip etc. And suitable for drill press, pistol drill, bench drill, vertical drilling machine, hand held electric drill, stand motor-driven drilling machine etc. Professional Tool Sets:Two spurs and center spur to give repeated, clean and accurate hole cuttingfor Woodworking, Furniture, Door Hinge Hole