This P100 grit quick-change sanding disc has aluminum oxide abrasive with durable YF-weight polyester backing that is water-resistant and resin-bonded for heat resistance. Ideal for use in welding, metalworking, maintenance, repairs, and operations, this roll-on sanding disc and can withstand grinding speeds up to 30,000 RPM and can be run wet or dry. This sanding disc is 1 1/2 inches in diameter.