Gator Power Plus 4-Pack 5" x 8 Hole 50 Grit Hook & Loop Sanding Discs are made with zirconium oxide abrasive for long life and durability. They are also resin bonded for added strength and resistance to heat. The hook and loop backing makes them easy to attach and remove from your sander. These discs are suitable for use on drywall, fiberglass, metal, and wood.