On Friday, 6 November 2020 at 14:58:48 UTC+2, waremark wrote:
"ACD Air Avionics Altimeter and more."
There is also the LXNav Air Data Indicator - combined altimeter and ASI.

With either of these devices, is there any battery backup? Is there a legal requirement for a battery independent system? Do you have to have any instrumentation separate from the flight computer since flight computers can display all of altitude/height, airspeed and vario, and can control radio and transponder?

LXNav states clearly that it is not certified. What a waste of panel space then.