Gator, 2 Pack, 3" x 21", 50 Grit, Aluminum Oxide, Sanding Belts, Designed For Heavy Duty Sanding & Grinding Of Wood, Metal, Fiberglass & Painted Surfaces, For Use On Power Belt Sanders, Bi-Directional Flush Joint Allows The Sanding Belt To Run Smoothly In Both Directions, Resin Bonding System Resists Heat & Humidity Extending The Life Of The Sanding Belt, Made Of Heavy Extra Weight Cloth For Maximum Strength.