I ordered a "tower" for an Inogen device for a friend and waited forever for it to arrive. I finally gave up and ordered another one from Amazon which arrived in about 2-3 days. A few days later my original order from Inogen arrived. I returned it for a refund to Inogen via Fedex Ground on June 21, 2021. Here is the tracking number: 280603****82. As of today, July 8, 2021, I have heard nothing from Inogen nor have I been refunded my money. Inogen makes a semi-good product but their service REALLY STINKS! The people in charge are too irresponsible to be handling products that people depend on for life-or-death situations. today User's recommendation: Stick with oxygen tanks.