แอร์ล็อคแบบ 1 ชิ้น อย่างดี – High Quality Airlock 1-Piece type

Airlock ๅ-Piece Type

Used with the fermenter to let the CO2 out of the fermenter and prevent O2 (also other contaminants in the environment) which will result in wort oxidation and/or contamination. All you need to do is fill the airlock halfway with sanitizer (some people fill with vodka).