3M Scotch-Brite non-woven SL-DH hook & loop disc uses aluminum oxide as the abrasive material and has a diameter of 5 in. Since this product is non-woven, Grade is generally used to describe the abrasiveness; with the 33809 having a coarse grade. 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 hook & loop disc can be run at a maximum speed of 10000.