Mercer Abrasives 627060-25 Type 27 Premium Depressed Center Grinding Wheels For Aluminum 4-1/2-Inch by 1/4-Inch by 7/8-Inch, 25-Pack Type 27 premium depressed center grinding wheels for aluminum Size: 4-1/2-Inch by 1/4-Inch by 7/8-Inch 25-Pack Aluminum grit Available in all different sizes and grits