LEORX 1.5-6.5mm High Speed Titanium HSS Quick Change Twist Drill Bit Set- 13pcs Material: Hard HSS with titanium nitride coated. Size: 1.5mm 2.0mm 2.5mm 3.0mm 3.2mm 3.5mm 4.0mm 4.5mm 4.8 mm 5.0mm 5.5mm 6.0mm 6.5mm. Titanium nitride coating facilitates faster penetration with less effort. The 14 "hex shank is designed for cordless screwdriver and allows you to change bits quickly. Suitable for steel, wood, plastic, etc.