Sait 100-Grit Premium Aluminum PSA Cloth Discs. Premium aluminum oxide grain. Strong X-weight Egyptian cotton cloth backing. Closed coat structure. Ferrous and/or non-ferrous metals (iron, steel, aluminum, copper, etc.). Stainless steel, high tensile steel. Tech Info: Strong resin over resin bond construction is resistant to heat and moisture. Hot melt adhesive back allows for quick change and less downtime.