The countersink drill bit is perfect for wood boards, fiber board, particle board, plywood, plastic, PVC and soft metalsThe countersink drill bit set is used for drilling quickly and precisely a hole. better in centering and no slipping These countersink drill bits are made of high carbon steel heat treated and tempered with titanium nitrate coating for excellent grinding ability Easy to use hex wrench combination to adjust or disassemble the drill bit from milling and chamfering of the five flutesA chatter-free chamfering tool to ensure easy chip removal and their drive edge are hardened and disturbed for sharpness Note: The data are all manual measurement, please allow 1 - 3cm error, due to the light and display difference, there will be some color difference, depending on the physical object received.