Mxsmanic wrote:

Is there a picture of the device somewhere on the Web? How do you
talk on the radio if you are wearing an oxygen mask, or is it just one
of those things that covers the nose?

it's a commercial site, the place where I bought my system, but it
should give you an idea: http://aviationoxygen.com/

there are different options depending on altitude: I use the cannula
which works well for as high as any aircraft I fly can go anyway :-)
(might be a limiting factor if I get back to flying gliders though);

you have masks with built in microphone too,

--Sylvain