Tiger Depressed Center Wheel, Performance Line, 4-1/2 in Wheel Dia, 1/4 in Wheel Thickness, 7/8 in Center Hole, Arbor Connector, 24 Grit, Coarse Grade, Zirconia Alumina Abrasive, Wheel Type Number: Type 27, 8500 rpm Maximum, Resin Bond, Applicable Materials: Carbon Steel, Structural Steel, Cast Iron, Steel and Stainless Steel, Wheel Hardness: T, Yes Reinforced, ANSI B7.1-2010 Specifications Met.Weiler’s high quality line of grinding wheels help metal fabrication professionals get the most demanding jobs done right and done fast.