Trisha has a doctors appointment tomorrow in Detroit and will need to take 2 tanks with her. Tanks only last 4 hours each. The portable oxygen concentrator came with 4 batteries that last about 3 hours each. You can either roll it or carry it with straps. So with this she's able to maintain a more normal lifestyle, and wouldn't have to switch them out every 4 hours! It is super easy to energize on the go. But they have to rent it by the week. To buy it costs over $5,000!! Insurance will not cover the portable oxygen concentrator instead of the tanks, since she's on oxygen more often lately!