Stefan "stefan"@mus. INVALID .ch wrote in message ...
The currently most advanced system is EDS-D1 by Mountain High
http://www.mhoxygen.com/

It's very popular among glider pilots because its sophisticated
pulse-by-demand-functionality reduces the oxygen flow considerably. Just
put the cannula on and forget it. Not cheap, but worth the price.

I second Stefan's endorsement of the Mountain High system. I've been
using one for 8 years in two different motor gliders and really like
it. The self-adjusting O2 flow and the longer bottle time (probably at
least twice an oxymizer) are great.

One other point if you buy it: I debated buying the 12v power kit so I
wouldn't have to replace 9v batteries all the time. Well, "all the
time" is less than once a year. And that's usually just to play safe,
not because the battery wore out! So I'm glad I didn't waste the money
and extra complexity for the 12v power kit. And I use the system much
more heavily than the typical GA use since, to gliders, altitude is
like fuel to a power plane.

Martin