Premium tough zirconia grain for extended life and material removal, High grain concentration ensures agressive grinding action and smoother running wheels, Proprietary wheel design for durable long life wheels, 3 full sheets of fiberglass for added durability and safety, Diameter: 4 1/2"", Edge Thickness: 1/4"", Arbor Size: 5/8-11"", Grit: Z24R, Application: Metal and Stainless Grinding, Max RPM: 13,300, SKU: ORSNO50243