Pentair 25010-0200 Air Relief Valve Assembly Replacement for select Sta-Rite Pool and Spa Filters Air relief valve assembly replacement Fits Sta-Rite PLM pool and spa cartridge aboveground filter System Fits with Sta-Rite System 2 Modular Media PLM Series pool and spa cartridge filters model PLM100,PLM125, PLM150, PLM175, PLM200,PLM300 Also fits with Sta-Rite Posi-Flo II PTM Series pool and spa cartridge filters model PTM50, PTM70, PTM100 and PTM 135 Air relief valve assembly comes with O-ring