Hayward SX360Z1 Bulkhead O-ring Replacement for Hayward Sand Filter Bulkhead o-ring replacement Fits hayward micro-clear vertical grid de and pro plus sand filter series s311sx, s311sxv, s360sx, s210s, s244s, s310s Also fits hayward super star clear cartridge filter series c2000, c3000, c4000, c5000 Weighs 3-1/2-pound