OMJ2015: Features: -Used for snagging and grinding ferrous metals.-Tool Shape: Type 1.-Arbor Diam: 3/8 in.-Abrasive Material: Aluminum Oxide.-Grit: 24.-Hardness Grade: M.-Applicable Materials: Cast Iron, Steel.-Mounting: Arbor Hole.-Type: Grinding Wheel.-Quantity: 15 per pack.-Testing and approvals:.-ANSI. Dimensions: -Thickness: 1/2 in.