The M400 works fine. No SD card needed, but you will need external
battery power for flights over 2 hours. If you have purchased a used
one, you will probably need to replace the battery.- Hide quoted text -

- Show quoted text -

I will second that. A new 750ma battery ($12) is a good idea if the
device has been a bit of service.

I purchased a new one, but then purchased the cord by Vladimir to run
the MIO from external 12V source, as well as to connect via RS232 to
Flarm (as well as Condor, etc, to get used to it).

I've heard of a few people using a 4AA battery box with a USB charging
plug on it to run these things for many hours. Have you tried this?

That will probably be the easiest solution for a rental glider in
which I will be flying all day. Just replace the AA's before the
flight.

Thanks
Tom