An Oxygen Geyser on Elpis in Borderlands: The Presequel (BL:TPS)

The Oxygen Geyser is an air source in Borderlands: The Pre-Sequel on Elpis

You just need to walk over it to refresh your O2 supply. They are found very commonly around most areas while on the surface of Elpis. These can also have enough force to launch you upwards.

They are marked as diamonds on the Map.