Coarse Polishing Disks, Mounted on mandrel, 1" Diameter, 5000 rpm, Package of 12 brush Disks. Does not damage the surface of the tooth. Must be used at 5,000 RPM so acrylics do not overheat. Coarse, medium, or fine options. Suitable for use with conventional polishing pastes. A unique polishing instrument that produces reliable results while being gentle with the tooth surface. This brush is recommended to be used at around 5,000 RPM for acrylics, so the material avoids overheating because of friction.