Norton Bench and Pedestal Grinding Wheel, Type 01, Series: 57A, 12 in Wheel Dia, 1 in Wheel Thickness, 1-1/4 in Center Hole, 46 Grit, Coarse Grade, Aluminum Oxide Abrasive, 2070 rpm Maximum, Vitrified Bond, Brown Wheel, Applicable Materials: 300/400 Series Stainless, Hard/Soft Carbon Steel, Tool Steel, Titanium, Superalloy, Aluminum, Brass, Bronze, Copper, Cast Iron, Ductile Iron and Gray Iron, Wheel Type Number: Type 1, Wheel Hardness: M