Pentair 270010061S Filter Tank O-Ring Fits Sta-Rite PLM pool and spa cartridge aboveground filter system Also compatible with Sta-Rite PLD pool and spa D.E. 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 System 2 Modular pool and spa D.E. filters which have PLD Series model PLD50 - DE, PLD70 - DE