SAIT® Saitech Attacker® Depressed Center Wheel, High Performance, 4-1/2 in Wheel dia, 1/4 in Wheel, Thread 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, 5/8-11 Center Hole Thread, Black Wheel, Reinforced: Yes, Specifications Met: ANSI B165.1, ANSI B165.2, ANSI Z87.1, OSHA 29CFR 1910.1200 SAIT® Saitech Attacker® 20146 High Performance Depressed Center Wheel, 4-1/2 in dia x 1/4 in Thick, 24 Grit, Ceramic Alumina Oxide Abrasive