Drum Sanding is used for smoothing the inside or outside of curved edges on project workpieces. This 2-5/16 Inch Shopsmith Sanding Drum is 3Inch long with a rubber expansive drum that can be attached quickly to the spindle on Your MARK, Shopsmith Power Station, or the auxiliary spindle on your Shopsmith Belt Sander. The 3” long sleeves are made with tough, long-lasting A/O Abrasive. Assorted 6-pack includes (2)each 60, 80, and 100 grit sleeves.