Vent carbon dioxide and other gases out of your container without letting dust, oxygen, and other contaminants in. Fill these airlocks with water or a sanitizing solution and they form a liquid seal. They’re often used in fermentation, such as beer and wine making, as well as other jobs where chemical reactions or temperature changes produce gas inside your container. A cap blocks out dust even as it vents the gas.

Push these airlocks into flasks, carboys, and other containers that have a rubber stopper with a hole. The airlocks come apart in three pieces for easy and thorough cleaning—no need for specially shaped brushes to reach every crevice.