Sta Rite, 25" Filter Tank Replacement O'Ring #24850-0009, 248500009, STA0512692. Fits: System 3 - DE, Cartridge or Sand mods: S8D110 S8M150 S8S70 S8M500 Sta Rite GENUINE Repacement Part by Super Pro (24850-0009, 248500009, STA0512692) Fits: (S8D110 S8M150 S8S70 S8M500)