I have recently started using liquid oxygen at 8lpm. I find that the flask I have doesn't last long. I am forever refilling the flask and I have been told that the maximum number of flasks I can have is 2. I would like to know how others have got on with liquid oxygen and how they arrange their outings to fit in with the 2 hour maximum usage from a flask. Maybe I should go back to my cylinder at 6lpm with a conserver. Please tell me your experiences.