Fish bubble oxygen cylind / Diving breathing oxygen bottle

This kind of oxygen cylinder can provide people with long and comfortable deep-sea diving without the discomfort of dry throats. It turns the surrounding sea water which is absorbed in advance to fresh water with filters and stores it up. When people feel thirsty, they can drink a little fresh water stored in the oxygen cylinder. However, if the storage of the fresh water is excessive, the gill filters on the oxygen cylinder can extract oxygen from the redundant fresh water.