Whirlwind USA GPST 5-Inch Heavy Duty Diamond Grinding Cup Wheel Premium Segmented Turbo Cup for Concrete Mortar with 5/8-Inch 11mm Thread (5") Used for heavy duty grinding concrete, mortar to remove glues, mastics and epoxies Can be used wet or dry. Premium segmented trubo cup wheel. 5/8-Inch 11mm thread Precision balanced for vibration free grinding and a smooth finish