4" Black Cap With Hole For Bung (not included), includes rubber seal.
CLICK HERE -> Bung
CLICK HERE -> Bubbler
23Ltr Degasser
Auto Syphon 23L
Auto Syphon Clamp - fits 23L Syphon
Auto Syphon Clamp - fits 4.5L Syphon
Black PVC Grommet For Airlock