Don't be fooled by other bags claiming to do what Kordon's Breathing Bags do - there are no "Second Generation Breathing Bags" that are produced from the same or improved material or that can claim the same Oxygen Transfer Rate as the Original Kordon Breathing Bags.
Breathing Bags are a completely new approach to the shipping of live fishes, as well as aquatic invertebrates and aquatic plants, in plastic bags. The special plastic film used in the Breathing Bags generates the constant transfer of carbon dioxide out of the water in the bag through the walls of the bag, and the absorption of oxygen from the atmosphere though the bag walls into the water in the bag. This provides a constant source of fresh oxygen for the breathing of the fishes and other aquatic life.
Kordon ® Breathing Bags™ represent a new approach to the problems of shipping live fishes and other aquatic animals and aquatic plants, including over long distances or for extended time periods. The product development staff at Kordon, teamed with plastics chemical engineers, have taken a technology first developed in space/military research and refined it to produce the bags being offered today.
The Breathing Bags allow the transfer of simple and complex gas molecules through the plastic wall of the bag -- carbon dioxide and oxygen in particular, as well as other gases - providing a true "breathing" bag in place of a "barrier" bag as is used in plastic polyethylene bags. As long as there is a breathable atmosphere outside the Breathing Bag, the animals inside will not run out of oxygen.
Carbon dioxide exits the bags at 4 times the rate oxygen enters the bags, thereby constantly purging the water of toxic carbon dioxide, and allowing oxygen to replace it in the water. Kordon has shipped around the world millions of bags (termed "Sachets") of living foods (tubifex worms, brine shrimp, daphnia, glass worms, etc.) for aquarium fishes using the Breathing Bag technology, and hundreds of thousands of Breathing Bags have been used successfully to ship fishes, coral reef animals, and aquatic plants.
Prior to this invention, the only plastic bags available for shipping fishes and aquatic invertebrates were made of polyethylene and had no mechanism to allow the passage of gasses through the bag wall. When using these "barrier" bags, any oxygen must - of necessity - be added as a gas inside the bag prior to sealing.
This process has many problems. High concentrations of oxygen can cause flammable conditions. The presence of oxygen gas inside the bag takes up a lot of valuable shipping space. Once the supplied oxygen is used up there is no more available.
Toxic carbon dioxide from the fishes' breathing builds up in the water, displacing the oxygen. The oxygenated air in the bags may not be satisfactory for fishes' breathing, because (particularly from sources in underdeveloped countries), the bottled oxygen may be contaminated. A bag partially full of water with the rest filled with oxygen allows the contents to slosh during transport, stressing fishes.