SAIT Saitech Attacker Depressed Center Wheel, High Performance, 4-1/2 in Wheel Dia, 1/4 in Wheel Thickness, 7/8 in Center Hole, Arbor Connector, 24 Grit, Extra Coarse Grade, Ceramic Alumina Oxide Abrasive, Wheel Type Number: Type 27, 13300 rpm Maximum, Resinoid Bond, Applicable Materials: Ferrous Metals, Stainless Steel and other High Tensile Alloy, Reinforced: Yes, Specifications Met: ANSI B165.1, ANSI B165.2, ANSI Z87.1, OSHA 29CFR 1910.1200