I had six units all of them broke down in the first 2 to 4 weeks. Always low oxygen output. You need the lifetime warranty for these units as they dont give you more then 60 to 80 hours of trouble free use. It is a very annoying machine getting replacements use it for a few hours and wait for the replacement to come in. I am shopping now for a reliable concentrator where i pay for quality not the name!

What about columns replacement? Is that covered under the forever warranty?

Everyone I see that have this G5 have all the same problem, and 02 error with the triangle sign.

Replacement cost

The info online states that it is 5.7 pounds.

It's top heavy. And it's noisy very loud compared to other brands

I weigh 80 lbs and I find it very heavy to carry around. You mention 4.5 lbs, it truthfully weighs 5.10 lbs with the carrying case and single battery. Much too heavy for me to have an easy, breezy walk around the block. Let's get real about what you're selling.

Very very heavy