O-Rings are used to seal the space around the lid of cornelius kegs to prevent carbon dioxide from escaping.
Cornelius Keg Lid
O-ring sizes for common Homebrewing applications
Cornie lid o-ring size 417 Common supplier: McMaster-Carr part #9396K926
Cornie post o-ring size 111 Common supplier: McMaster-Carr part #9396K24
Cornie dip tube o-ring size 109 Common supplier: McMaster-Carr part #9396K74
