3M Scotch-Brite ceramic RD-ZB bristle disc is measured using outside diameter (OD), with the OD being 2 in. The quick change attachment allows for easy mounting to the tool or pad. 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 bristle disc can be run at a maximum speed of 25000 RPMs.