Tiger Ceramic, 58325, Depressed Center Grinding Wheel, Performance Line Superior Life and Cut, 4-1/2 in Wheel Diameter, 1/4 in Wheel, 7/8 in Center Hole, Arbor Connector, 24 Grit, Coarse Grade, Ceramic Alumina Abrasive, Wheel Type Number: Type 27, 13300 rpm Maximum, Resin Bond, Applicable Materials: Tool Steel, Inconel, High Nickel Alloy, Titanium, Armored Steel, Stainless Steel and Hard-to-Grind Metals, Specifications Met: ANSI B7.1-2010