Super Major Airlock for Wine and Beer Making by Young's.
This airlock has a very large water chamber making it ideal for forgetting about, without the risk of it drying out. Some people also find these airlocks easier to clean than bubbler airlocks.
Fits all standard bored Rubber or Cork Bungs.
Just half fill with water. When fitted, the Super Major Airlock protects the ferment by allowing a visual passing of gas pressure to escape but admits no air.