SAIT Blue Line Abrasive Disc, Close Coated Premium, 7 in Disc Dia, 7/8 in Center Hole, 36 Grit, 3Z Zirconium Abrasive, Fiber Backing, Applicable Materials: Aluminum, High Tensile Steel, Stainless Steel, Titanium, Ferrous and Non-Ferrous Metals, 8500 rpm Maximum.