Scotch Brite 3M radial bristle disc, grit 120. The three-dimensional abrasive/flexible bristle design provides a uniform finish; stack between three and six discs on one mandrel to create the width that best suits your task. Use them for heavy cleaning, for removing firescale and light oxide, and for pre-polishing, semi-finishing, blending, texturing and polishing. Discs provide the convenience of a pre-charged abrasive but don’t generate the heat associated with rubber wheels. 9/16".