Trimix family : Hyperoxic Trimix
Hyperoxic Trimix, sometimes called “triox” or “helitrox” are prepared with a higher proportion of oxygen than the usual 21%.
The most popular concentration is called 26/17 Trimix for 26% oxygen, 17% helium and 57% nitrogen.
It requires decompression stops similar to Nitrox 32 and has a max operating depth (MOD) of -44 m. It is breathable on the surface and is mostly in use for shallow dives or to optimize the decompression time when ascending.