【Professional Twist Drill Bits】: 13-piece set: 1.5mm (1/16"), 2mm (5/64"), 2.5mm (3/32"), 3mm (7/64"), 3.2mm (1/8"), 3.5mm (9/16"). 162.6 cm (64"), 4 mm (5/32"), 4.5 mm (11/64"), 4.8 mm (3/16"), 5 mm (13/64"), 5.5 mm (7/32"), 6 mm (15/64"), 6.5 mm (15/64"). /4" High-quality material: The bits are made of titanium-coated high-speed steel, which offers excellent heat resistance and long life. Quick bit change: The 6.35mm hex handle is suitable for all power tools, making it easier, more comfortable, and safer to use. It is suitable for electric screwdrivers, drill bits, etc. or for standard drill chucks. Even drilling: Designed with a 135° cutting angle, it can automatically center and penetrate quickly with light pressure. The threaded flutes can remove chips and debris faster.