 It is sometimes referred to as "poor man's trimix", because it is much easier to blend than trimix blends with variable oxygen content, since all that is required is to insert the requisite partial pressure of helium, and then top up with air from a conventional compressor.The more complicated (and dangerous) step of adding pure oxygen at pressure required to blend trimix is absent when blending heliair.Heliair blends are similar to the standard Trimix blends made with helium and Nitrox 32, but with a deeper END at MOD.