Thank you

B Sherpherd, please understand that the numbers on the Inogen only are numbers. They do not equate to LPM. The G-5,. which is the most powerful of all the Inogen POCs only produces 1.26 LMP AT MAX. Please do your research!

Inogen Concentrators up to 4 lpm has 2 2 hour batteries available...5lbs..easy to transport ..very pleased...

If your husband needs 3 LPM continuous, there are only two or three machines that will produce that much O2, and they are all heavy and require carts to move around. None of the small, lightweight machines will produce O2 at a rate that will keep him saturated, unfortunately. There are a number of people pushing research in this area, but not enough is being done. I recommend you visit www.pulmonarypaper.org and review the spring summer issue for 2020 (there should be a new on in May for 2021). You will at least understand the issues involved.

I am on 3 lpm continuous....have s Sequal Eclipse 5 and 3 is its highest setting. Its very heavy to pull/push around. The short battery life is a HUGE problem as it prevents me from flying to see my family. A second battery ($500!) would still not be enough for a flight of several hours plus airport time.
Your husband might need to find a cart he could use with a tank.