Oxygen becomes a liquid at about minus 368 degrees Fahrenheit . At this temperature it takes up a tenth of the space of compressed oxygen. Using liquid oxygen, your oxygen provider will set up a liquid oxygen reservoir (Dewar)in your home.
Then arrange visits to fill the reservoir how often this happens depends on prescription and evaporation that happens without using any.
Fill a portable unit from the reservoir it takes around 15 mins before the portable should be used after filling allow extra time if your using high flow rates.
Liquid oxygen is safer to handle than compressed oxygen because it's stored under far less pressure than compressed oxygen (21 psi vs. 2,000 psi). So long as the vessels containing liquid oxygen are upright, they are safe though frost may appear on the bag it's not leakage.
There is a danger of burns to the skin should you touch the very cold ports while filling caused by the very low temperature which keep the oxygen liquid.
In use the liquid oxygen boils at about minus 297 degrees Fahrenheit becoming the gas that can be breathed in through a mask or cannula.