Item Type: Countersink Drill Bit Set Material: Drill Bit 4241 High Speed Steel, Countersunk Drill Bushing 45 Steel Surface Treatment: Surface Titanium Plated Treatment Blade Diameter: 7/64in, 9/64in, 11/64in, 3/16in, 7/32in Drill Bushing Hex Shank Diameter: 1/4in Package List 5 x Drill Bit With Drill Bushing 1 x Wrench Do a good job of safety protection when using 1Excellent Cutting Power: This is a counterbore drill with excellent cutting power, high durability and good wear resistance 2Titanium Plating Treatment: The surface of countersunk drill bit is treated with titanium plating, which is corrosion resistant, good toughness, and high strength 32 Chamfering Grooves: The drill bit is accurately inserted into the countersunk socket, and the 2 chamfering grooves enable faster operation and self cleaning drilling on chips 4Ideal Choice: This countersink drill bit is an ideal choice for bench drills, hand drills and traditional electric drills, convenient and efficient 5Wide Application: Counterbore drill is very suitable for wood, fiberboard, particle board, plywood, plastic, PVC, rubber, etc.