The Handy Small Airlock from Youngs is perfect for wine and beer making, it helps keep an airtight seal on your fermenting vessels. This airlock can fit a rubber or cork bung, when you fit it after filling it half with water, it then protects the ferment by allowing a visual passing of gas pressure quietly. It traps the air, in order to help the process of creating delicious wine or beer! Handy Airlock Small 5290 Features Youngs Handy Airlock Small 5290 Airtight seal Not suitable for plastic demijohns Youngs\' Ref. MPN: 5290Colour: ClearSizes: One SizePM Ref: 844187