The Blacketts Aerorphor was last used in 1968 when it was replaced by the Aerorlox (again I used Aerorlox a lot), and my father who thankfully is still alive used the Aerorphor, so I will get some stories from him, he was a rescue station superintendant (the boss).
It was a 2 hour unit using liquid air instead of oxygen, but it started off at 60% oxygen / 40% nitrogen, but because over time the nitrogen bioled off quicker, it was nearly pure liquid oxygen by the time you got to use it. It held 5.5 lbs of liquid air in the upper back container, the lower rectangular container was the Caustic CO2 absorbant used.