Mercer Abrasives 620190-5 Type 27 Depressed Center Grinding Wheels 9-Inch by 1/4-Inch by 5/8-Inch - 11, 5-Pack Type 27 depressed center grinding wheels Size: 9-Inch by 1/4-Inch by 5/8-Inch - 11 5-Pack Metal grit Available in all different sizes and grits