Features: Creates a closed system that allows carbon dioxide out and prevents oxygen and harmful bacteria from getting in. Lets fermentation gas out and to keeps air from reaching the beer or wine. Very durable and easy to clean, safe to use. Compact and lightweight size, easy to be stored and saves space. Perfect for secondary fermentation, preventing back-flush into the fermentation chamber during ambient temperature changes in the room. They are standard size airlocks made to fit any homebrew stopper, cork, cap, plug, bung, or a grommet with a 3/8" hole. Works great for beer, wine, and shine. Specifications: Material: PP Height: 4.6in (12cm) Width (at widest point): 1.5in (3.8cm) Airlock Stem Length: 1.5in (3.8cm) Airlock Stem Width: 0.44in (1.11cm) This airlock is made of thin, light-weight plastic and is fragile. Care must be taken not to drop it or exert excessive pressure on it. Packing list: 1* airlock Note: 1.Due to the different monitor and light effect, the actual color of the item might be slightly different from the color which is showed on the pictures. 2.Please forgive 1 cm/0.39"-3 cm/1.18" measuring deviation due to manual measurement.