3M COW cutoff wheel uses aluminum oxide as the abrasive material and has a diameter of 4 in. In addition to the other aspects of these parts, another important component of these is the thickness. This 3M part is 0.06 in thick. 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 cutoff wheel can be run at a maximum speed of 21000.