Made of high-quality materials, .The drill is made of heat-treated and tempered carbon steel, which has excellent cutting force and durability, and its accuracy is higher than that of ordinary drills. The countersunk has an automatic starting point, and the five-slot design eliminates chatter and vibration, and makes the operation smooth, thereby achieving clean, accurate and burr-free cutting. You can drill the screw hole and counterbore of the nut at the same time, and keep the two on the same axis. After tightening the nut, the nut is located below the plane of the circuit board. The standard 1/4-inch hex handle can be quickly replaced, and the depth of the second sleeve can be adjusted by covering the matching plug with a flat- screw Hex key or a cover. Eject wood chips faster, you can get a smooth on any type of hard, cork or aluminum.Suitable for workpieces with hardness lower than 25HRC, such as carbon steel, thin iron plate, insulating plate, PVC plate, wood board, etc. Product parameters: Countersink drill size: 5#, 6#, 8#, 10#, 12# Diameter of countersunk drill: 1.98mm (approximately), 5/64inch drill bit, 3/8inch countersunk screw, for screw size: #5 2.38mm (approximately), 3/32inch drill bit, 3/8inch countersunk hole, for screw size: #6 2.78mm (approximately), 7/64inch drill bit, 3/8inch countersunk hole, for screw size: #8 3.175mm (approximately), 1/8inch drill bit, 3/8inch countersunk hole, for screw size: #10 3.56mm (approximately), 9/16inch drill bit, 1/2inch countersunk hole, for screw size: #12 Colour:Black + Gold Material:Carbon steel Package Contents: 4* claw corkscrews 4* Claw cork drills 1* wrench Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.