Oxygen Concentrator is such a machine than can simultaneously supply oxygen gas generators. It is also called the oxygen generator machine. This machine operates with the help of electricity. It does not need to be rflled. It can be used only if you buy the electric machine and give it a current connection to the house. This machine can supplyup to 5 liters of gas in 1 minute. The interesting fact is that it can be brought anywhere as it is portable. 

Oxygen Generator Concentrator