My partner / husband has Pulmonary Fibrosis which is obviously different than COPD but they share many characteristics. I got here by way of Google looking for information about portable oxygen concentrators and continuous flow vs pulse dose. My partner is at the point where any activity such as going to the bathroom will cause him to desat down to the 70s. The way he recovers is to use an oxygen mask which is connected to the large home concentrator. He otherwise uses the Inogen 3 portable concentrator 24/7. He has not been out of the house (or even out of the bedroom) for over 2 months and I'm afraid the Inogen will not be enough the next time he has to go to a doctor's appointment. I have been looking at the SeQual Equinox. It seems to fit the bill. It has continuous flow up to 3 lpm if we have to switch to the mask (our home concentrator is set at 5) but it sounds like with the "super" pulse settings (7-9) he might not even need to do that. Unfortunately I have so far been unable to find a vendor who rents that out by the month and takes insurance as Inogen does. Before I spend the money to buy one I want to have an idea if it would work. Any advise would be helpful.