• Manufacturer: Sta-Rite 

• Type: Replacement O-ring 

The Sta-Rite 35505-1425 System III Bulkhead O-ring is a compatible pool O-ring for System 3 Modular Media SM series cartridge filter models S7M120, S7M400, S8M150, and S8M500; System 3 Modular SMD series D.E. filters; System 3 SD series D.E. filter models S7D75 and S8D110; and System 3 SS series sand filter models S7S50 and S8S70.