Has anyone had any experiance with oxygen systems for a cessna 172. I am looking for a 4 place system to cover kids, so thay don't feel left out, but will be using it mostly solo. I do a lot of mountain flights and night flights ... for work transport, rarely above 14,000 DA and am feeling the effects of time on my body (ie I'm getting younger every day...). I am looking at the "Aerox Oxygen Systems AO 4M" 22 cu ft 5.5" x 19" amd a tight fit between the seats. Any experiance or comments out there?