1,to store marsh gas,carbon dioxide gas 2,easy to move and storage after folded 3,any size ... when the tank is full.It can be used to store and collection industrial gas, biogas as a gas supply ... be folded when empty, the weight light and easy to transport, on-site installation is simple, long life and ... .29051000203eGAS 20000L2.15.8490.35We can according to customer requirement to custom-made. gas tank