United Abrasives- SAIT 61151 Closed Coat Aluminum Oxide 3-1/2-Inch x 15-1/2-Inch 1-AX 120 Grit Sanding Belt, 10-Pack 1A-X/2A-X: Aluminum Oxide, closed coat, X weight cotton. For general purpose sanding grinding and finishing of ferrous and non-ferrous metals, wood, cast iron, ordinary and alloyed steels and stainless steel.