Upgraded Transparent Air Lock - Unlike other ordinary 3-piece air locks on the market, it is made of healthy materials, harder and more transparent. You can easily see the entire fermentation process. Fill the airlock 1/2 full with water, close the lid, and insert the lid. It fits perfectly with #6 grade brakes, has no leaks, is nice and strong. (Please consider whether your container will fit our extra stopper sizes before purchasing.) The 3-piece air lock is perfect for the main fermenter because it comes apart for easy cleaning while blowing. If you want to maintain a boat-shaped home brewing operation, a 3-piece airlock is the only option. Taking them apart and thoroughly cleaning them is a breeze. Why use it for fermentation - There are very few bad things in the fermentation process. Since the fermentation process should take place in an anaerobic (air-free) environment, it is key to food . Colour:As Shown Material:Plastic+Silicone Package Contents: 1 set * disc airlock locks Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.