What is anaerobic fermentation?

Oxygen Graphic Anaerobic fermentation means “absence of oxygen”, the opposite of aerobic fermentation

Pickl-It was designed to create and maintain anaerobic fermentation, its wire-bail/airlock combination locking out oxygen’s entry, as well as releasing oxygen from the fermenting chamber, pushed by carbon dioxide, out through the airlock. Two-part metal canning lids or screw-on plastic covers, do not have a sufficient seal in order to maintain anaerobic conditions.

Lactic-acid bacteria, responsible for creating a healthy, stable fermented food, thrive in a low or no-oxygen environment, described here.