Nitrous Oxide, Helium Gas, Ethylene Gas manufacturer / supplier in China, offering 10L - 50L Helium Calibration Mix Gas, 10L Industrial Helium Gas 99.999% Purity at 150bar/200bar Pressure, 5n/6n 10L Helium Gas 99.999% / 99.9999% at 150bar / 200bar and so on.