4 x 48 Inch Standard Metal Sanding Belts, 3 Pack. Aluminum Oxide (A/O).Premium Aluminum Oxide (A/O) with special embedded grinding aid. Closed coat, heavy duty X weight cloth backing. High quality and long lasting industrial abrasive sanding belts work great on non ferrous and ferrous metalworking applications including Aluminum, Titanium, Brass, Bronze, Copper, Steel, Stainless Steel, Cast Iron, and Carbon Steel. X-wgt material provides stiff backing for working with dense metals. Resin over resin bonding. Bi-directional tape joint. Dry applications. Assembled in USA.