Why is it so complicated to lock the DUO?

It is advised to hold the top of the carbonating head down while locking the flask for easy closure, applying pressure as needed.


The DUO Sparkling Water Maker’s safe design ensures that the flask-locking mechanism is working properly by ensuring that the protective flask is sealed in the rare case of a bottle failure. It also allows for easy movement between the flask ring and the flask. You may notice a small gap (about 2mm) when closed.