A&H Abrasives 817787, Sanding Discs, Aluminum Oxide, (x-weight), 10x3-1/2" PSA Aluminum Oxide 120 Grit Cloth Sander Disc Premium sanding discs for fast and smooth finishing. Specifications: Diameter=10 in, Shape=ROUND, Attachment Method=PSA Specifications: Bore Diameter=3-1/2 in, Grit=120, Abrasive=ALUMINUM OXIDE Specifications: Abrasive Bond=PHENOLIC RESIN, Backing=CLOTH, Backing Weight=X