... packed according to demand Name: helium gasPurity: 99.9~99.999%Property: colourless, odourless, non-flammable, non-reactive, inert gas Application: ... times faster than air, it is used as a tracer gas to detect leaks in high-vacuum equipment (such as cryogenic tanks ... Helium, mixed with a heavier gas such as xenon, is useful for thermoacoustic refrigeration due to the resulting high heat capacity ratio ...