Rex-Cut 245042 Grinding Wheel, Type 27 Depressed Center, Outside Diameter: 4-1/2 Inch, Thickness: 1/4 Inch, Arbor Hole / Thread Size: 7/8 Inch A.H., Grade: GFX (Soft), Grit: 36 (Coarse), Abrasive Type: Aluminum Oxide, Bond Type: Rubber, Max Speed: 13300 Rpm, Mounting: Arbor, Product / Materials Abraded: Stainless Steel/Aluminum