Tonsiki 4Pcs HSS 5 Flute Carpentry Countersink reamer Drill Bit Set Screw Woodworking Chamfer Tool 3-6mm Four piece set includes bits for drilling pilot holes for screw sizes 3mm, 4mm, 5mm, 6mm Special designed steel counter sleeve countersinks or counter bores pilot hole. Chamfer is 5 flutes,In the process of using, can discharge the wood more rapid Drill and countersink for wood screws without changing bits.