3M Cubitron II coated 982C quick change fibre disc uses ceramic precision-shaped grain as the abrasive material and has a diameter of 5 in. 3M incorporates this ceramic precision-shaped grain material into the quick change fibre disc forming a grit of 36. All abrasive products that rotate or spin, such as the ones in this category, have a maximum speed at which you can run them. This 3M quick change fibre disc can be run at a maximum speed of 12000 RPMs.