When replacing O-rings for carboy fermenters ensure you purchase the correct O-ring. O-rings come in different sizes to fit various carboys:
AMPI - 10mm thick with a 245mm diameter
Atlas - 7mm thick with a 270mm diameter
BMW/Rheem - 10mm thick with a 190mm diameter
Davis - 8mm thick with a 245mm diameter
VB - 8 mm thick with a 220mm diameter
* Make sure you measure the O-ring you want to replace so your new O-ring is a correct fit!
Suits: Ampi,VB,Atlas,Rheem,BMW carboys.
One piece Sbend Senior airlock/bubbler.
Three piece tapered shank Senior airlock/bubbler.
Lid O'Ring: 10mm thick, 245mm diameter. Suits 15lt, 30lt, ...
Medium size thread fits standard fermenter 3/4" BSP thread