High Efficiency: Countersink Drill Bit Set Countersink Drill Bit with Depth Stop, with a center drill, quickly discharges chips from the hole. It can effectively prevent debris accumulation and improve drilling efficiency. Practical Function: HSS Spiral Flute Drill Bit Set with a center drill quickly discharges chips from the hole. It can effectively prevent debris accumulation and improve drilling efficiency. High Quality: The HSS wood hole saw drill bit is made of high quality alloy steel with higher precision, higher hardness, faster cutting speed and greater force than ordinary drill bits. Wide Use: Woodworking countersink drill bit set is suitable for drilling holes in wood, ideal puncher for solid wood, particle board, plywood, MDF. Also suitable for plastic, soft metal, fiberboard, etc. Removable and Adjustable: Remove the screw with the included hex wrench and adjust the length of the countersunk hole to adjust the drilling length of screws of different lengths.