LOX

Liquid Oxygen

See Wikipedia's page.

Boiling point of -182.95°C (90.20 K).

Critical temperature of -118.59°C (154.59 K) meaning that it cannot stay liquid above this temperature.

1 Litre of LOX provides 840 Litre of GOX (gaseous oxygen) at 1atm/20°C.

Like any liquid, LOX vaporizes when stored above its boiling point. The vapour builds up to pressure that the tank will no be able to contain, so a relief valve must be put in place to compensate this evaporation. Insulation limits the rate of vaporization, the best being the vacuum space between a tank inner and outer walls, like Dewar flasks.