Hayward ECX4077B1 Check Valve For Perflex(R) Extended-Cycle DE Filter; EasyClear(TM) and StarClear(TM) Cartridge Filters and ReGenX(TM) Grid Element DE Filters
Perflex® Extended-Cycle D.E. filters clean pools fast, removing particles as small as two microns the first time through. Its patented Flex-Tube design gives longer cycles between cleaning because the same D.E. filter powder is used over and over.