Recessed Grinding Wheel Type 7 Recess Type Two Sides Diameter 12 In. Thickness 2 In. Arbor Hole 5 In. Recess Dia 7-1/2 In. Recess Depth 1/2 In. 2nd Recess Depth 1/2 In. Abrasive Material Aluminum Oxide Bond Type Vitrified 46 Grit Grade Coarse Hardness Soft (H) Max RPM 2070 Purple Series 32A Specification 32A46-HVBE