Aluminum oxide grain provides a fast cut with long life, stearate coating and semi open coat structure prevents loading.80-150 Grit: ????????????????????????????????heavy-weight, low flexibility paper backing 180-400 Grit: ????????????????????????????????medium-weight, low flexibility paper backing.For automotive body work, removing varnish from wood, sanding fiberglass, and for use on metal.For use on random orbital or low speed DA sanders ????????????For dry use only.Available in PSA Disc Rolls., Strong resin over resin bond construction is resistant to heat and moisture.This special sharp and durable grain cuts fast and lasts long.PSA Disc Rolls: Perforated for easy disc tear away from roll. Packaged 1 roll per box.Backing Pads for Paper Discs are available in Accessories.