The filter cap and purge valve are a replacement for Bestway and Flowclear 530, 800, 1,000 and 1,500 gal. cartridge pumps. It is also a replacement for the filter pumps that are included in select H2OGO!, Fast Set, Steel Pro, Steel Pro MAX, Power Steel and Coleman pool sets. The replacement cap screws onto the pump’s body to prevent water leakage. The replacement valve will screw onto the top of the filter cap to discharge air when maintaining the pump.