Excellent quality, made of tungsten steel and heat treated. High hardness, sharp edge, high precision, smooth cutting, impact resistance, and high toughness. The curved design of the drill bit helps remove chips and allows for more efficient drilling. The set includes 6 sizes: 30, 35, 40, 45, 50, and 60 mm. Compatible with pistol drill, bench drill, portable electric drill, manual electric drill, motorized drilling machine, and moving ribbon type magnetic drilling machine. Widely used for drilling flat bottom holes accurately without chipping in softwood of any thickness. Suitable for spherical door and drawer tip mounting, as well as perforation in wooden products, plastic products, wood, and plywood. Easy to store and select.