Gator 5-Pack 3" x 21" 50 Grit Aluminum Oxide Sanding Belts are designed for use on wood, metal, fiberglass, and painted surfaces. It is made of heavy extra weight cloth for maximum strength and has a resin bonding system that resists heat and humidity, extending the life of the sanding belt. The bi-directional flush joint allows the sanding belt to run smoothly in both directions. It is suitable for use on power belt sanders and bench top sanders.