Scotch-Brite(TM) PD Surface Conditioning Disc, 4 1/2 in x NH A CRS, 50 per case A lofty, open non-woven abrasive disc resistant to loading on soft and/or oily materials. Contains a backing that mounts to hook and loop pads. Abrasive mineral: Coarse grade aluminum oxide. Color: Brown MOS: 12000 RPM