I love my B40 as a backup vario. I traded out my winter for it a few
years ago after having a power problem take out my main vario about
100 miles from home. After flying home with just the winter it traded
it for the B40 so that I would have an audio if that happened again. I
change out the 9V battery every year when I do the annual.

I installed the averager switch for the b40 so normally I just use it
as an averager but if my main vario fails and I can switch it over to
the vario mode.

Brian
HP16T N16VP