Diamond Grit Range: Super Rough: 60#, 80#; Rough: 100#, 120#; Medium: 150#, 180#, 240#, 320#, 400#; Fine: 600#, 800#, 1000#, 1200#; Super Fine: 1500#, 1800#, 2000#, 3000#. Specifications: Diameter: 6" (150mm) Arbor: 12.7mm (could be modified for special needs) Thickness: 1.0 - 1.3mm Materials: Carton Steel Maximum speed: 3000m/s Precautious: Once the grinding disc has been installed, please have the machine idling for about 30s ~ 60s first. Application: Specially designed for grinding and polishing the surface of precious stones like agalmatolite,crystal, jade,agate, carvible tones etc. Also widely used in glass, ceremics, electronics, optoelectronics, tubes, engraving knife, hard alloy, handicrafts, crystal lighting, precision machining and other hard crumbly materials. Diamond grit description: Smaller grit(like #240) is for rough grinding, and larger grit is for precise grinding(like #600). For engraving knife or carvible stones grinding, it is suggested to start rough grinding with #240, and then choose #600 or #1000 for precise grinding. After that, #2000 is also applicable for final precise grinding. Pls be sure rough grinding first, precise grinding second.