Tiger Depressed Center Wheel, Performance Line, 9 in Wheel Dia, 1/4 in Wheel Thickness, Quick-Change Connector, 24 Grit, Coarse Grade, Zirconia Alumina Abrasive, Wheel Type Number: Type 27, 6600 rpm Maximum, Resin Bond, Applicable Materials: Carbon Steel, Structural Steel, Cast Iron, Steel and Stainless Steel, 5/8-11 Center Hole Thread Size, 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.