Walter Surface Technologies XCAVATOR™ Depressed Center Wheel, Ultra High Removal, 5 in Wheel Diameter, 1/4 in Wheel, Thread Connector, 16 Grit, Extra Coarse Grade, Zirconia Alumina Abrasive, Wheel Type Number: Type 27, 12200 rpm Maximum, Resinoid Bond, Applicable Materials: Alloy, Cast iron, Stainless Steel, Steel, Tungsten and Hard Metal, 5/8-11 Center Hole Thread, Specifications Met: ANSI B7.1, EN 12413