The Mr.Beer® LBK fermenter as well as our 8LX and 24LX fermenters do not have a traditional "airlock". However, our fermenters have been specially designed to automatically release and excess CO2 produce from the fermentation process and keep out contaminants. Positive pressure produced during the fermentation process keeps airborne contaminants from entering the vessel. For best results, keep the vessel at a constant temperature within the temperature for the entire duration of the fermentation process.
The LBK will leak from under the lid when you turn it upside down, there are two divets in the top of the neck that allow out gassing between the lid threads.