Head Lock Screw, Material Application Concrete, Optimal Performance for Material Various Materials, Product Type Head Lock Screw, For Use With PG 820, Application Concrete Grinding, Compatible with Grainger Part Number 18G371, 18G382, 18G389, Compatible with Manufacturer Part Number PG 530, PG 540, PG 680, PG 690, PG 690 P, PG 820, PG 830, Includes Head Lock Screw, Material Various