Metabo® Flexiamant Depressed Center Wheel, General Purpose, series: Original Grinding®, 6 in Wheel dia, 1/4 in Wheel Thickness, 7/8 in Center Hole, Arbor Connector, A24N Grit, Coarse Grade, Aluminum Oxide Abrasive, Wheel Type Number: Type 27, 10200 RPM Maximum, Resin Bond, Applicable Materials: Steel and Ferrous Metals, Wheel Hardness: N, Yes Reinforced. Metabo® Flexiamant 616554000 Original Grinding® General Purpose Depressed Center Wheel, 6 in dia x 1/4 in Thick, 7/8 in Center Hole