Nathan Young wrote:

No experience with any of the electric gyros, but the 1st one contains
a battery backup in case the electric source dies.Â*Â*SinceÂ*thisÂ*would
be a backup to your vacuum ADI, I think that's overkill.Â*Â*IÂ*wouldÂ*not
pay $2000 extra for it.

The battery is an option. The price is a little below $4K w/o, and a little
above with. Why one would get this w/o the battery, though, I'm not sure.
Sure, a failure of both electric and vacuum isn't likely. But the battery
option isn't that much more money.

Look at the MTBF. I think that the Mid-Continental has one that's longer
than most at 7500 hours. However, also check the warranties. I seem to
recall that there was a unit that seemed less robust than the MC unit but
which had a longer warranty.

- Andrew