Tiger Zirc, 58073, Depressed Center Grinding Wheel, Performance Line, 5 in Wheel Diameter, 1/4 in Wheel, 7/8 in Center Hole, Arbor Connector, 24 Grit, Coarse Grade, Zirconia Alumina Abrasive, Wheel Type Number: Type 27, 12200 rpm Maximum, Resin Bond, Applicable Materials: Carbon Steel, Structural Steel, Cast Iron, Steel and Stainless Steel, Wheel Hardness: T, Reinforced: Yes, Specifications Met: ANSI B7.1-2010