Countersink Drill Bit Set: Includes 8pcs countersink drill bits in 7 different sizes (3mm/4mm/5mm/6mm/7mm/8mm/10mm) with hex key. With numbers on the drill bits for easy recognition, can meet your different needs. Quality Material: The countersink drill bits are made of high carbon steel which features high hardness, superior cutting power, good abrasion resistance. Fast Chip Removal: The countersink design Three-pointed design ensures precise and fast drilling without offset, slippage and skew; Hardened and sharpened 5-edge chamfer cutter ensures easy chip removal. With smooth countersink drilled at once to save your time and labor. Removable and Adjustable: It is easy to adjust or disassemble the countersink drill bit and five-flute chamfering with the provided L-shaped hex wrench. Wide Applications: The woodworking countersink drill bit is widely used for plastic, PVC, rubber, particle board, hardwood or parquet, etc. And it fits drills with chuck, most bench or hand drills.