These premium aluminum oxide grain sanding discs are manufactured with the highest standards in the industry and are designed for heavy duty sanding and grinding of wood, metal, fiberglass and painted surfaces. The resin bonding system resists heat and moisture, which extends the useful life of the sanding discs. - Aluminum oxide durable grains are recommended by professionals for sanding a wide variety of surfaces like wood, metal, fiberglass, and painted surfaces - The hook and loop backing makes changing discs quick and easy - The vented hole pattern matches the sanders pad for maximum dust extraction - The discs are resin-bonded to resist heat and humidity for longer life