BI-DIRECTIONAL Sanding Belts - Aluminum Oxide.MADE IN AMERICA. The price you see for sizes 3 x 21, 3 x 24, 4 x 24 and 4 x 21 are for a BOX OF 10, all other sizes are per belt. The belts listed are our most popular sizes. However,If you don't see the size you're looking for, give us a call. We are an abrasive converter. In other words, we buy abrasives in rolls and can convert them to any size you need. All sanding belts shown are Aluminum Oxide. Please give us a call if you need a quote on Silicon Carbide (Wet/Dry) abrasives or Zirconia (metal sanding) abrasives.