3M coated 236U hook & loop disc uses aluminum oxide as the abrasive material and has a diameter of 6 in. 3M incorporates this aluminum oxide material into the hook & loop disc forming a grit of P220. 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.