100% brand new and high quality. Maximum RPM: 20,000. Made from strong HSS high-speed-steel, durable and firm. Ideal for cutting hard materials like wood, plastics, laminates and aluminium, etc. Suitable for use in carpentry and crafts. Size:Hole diameter: 6.35mm. Mandrel diameter: 3.2mm/6mm. Blade Diameter:22mm, 25mm, 32mm, 35mm, 44mm, 50mm.