3M Stikit coated 236U PSA disc roll uses aluminum oxide as the abrasive material and has a diameter of 5 in. 3M incorporates this aluminum oxide material into the PSA disc roll forming a grit of P220. This item is on a paper backing, C weight. 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 PSA disc roll can be run at a maximum speed of 12000 RPMs.