CGW® Surface Grinding Wheel, 2-Side Recessed, 12 in Wheel dia, 2 in Wheel Thickness, 5 in Center Hole, 46 Grit, Medium Grade, Aluminum Oxide Abrasive, 2228 rpm Maximum, Wheel Hardness: H, Vitrified Bond, Wheel Type Number: Type 7 CGW® 37716 2-Side Recessed Surface Grinding Wheel, 12 in dia x 2 in Thick, 5 in Center Hole, 46 Grit, Medium Grade, Aluminum Oxide Abrasive