Modern technology replacement for mechanical variometers.
The instrument has considerable hardware commonality with the B300/400.
The extended features over the B300/400 are:
- Better sensitivity in mid range than typical mechanical or LCD varios.
- expanded audio sensitivity in low climb range.
- LCD Average integrator.
- Emergency standby power pack (7-8 hours).
Built in audio, push button averager (besides the LCD averager) and unique to Borgelt Instruments, climb optimiser (green light with left and red light with sink).

With the top right button the audio can be adjusted, and with the lower left button the average can be displayed (20 sec average) while the variometer audio continues.
Because of the display's colors it provides better resolution and contrast than all LCD displays.
The pointer is made sharp and smooth for a faster recognition of lift and sink.
A standby power pack of 4x AA alkaline batteries will provide at least 7-8 hours of operation in the event of main power systems failure.
Also a loose speaker is included.

Vario style selection can be made by a small potentiometer accessible through a small hole in the rear cover of the instrument.
Options are:
- Full range audio, with silent zone from -0.5m/s to -2m/s.
- ''Up'' only audio B40, with solid tone in sink and 50/50 tone in lift.
- 'Up'' only audio Competition, with clicking audio on sink below -5m/s.

Vario can be used with static and TE pressure.

The only difference compared to B700 is the scale, where the B900 has a linear scale the B700 has a logarithmic scale.

Technical data:
Screws: 2x M4
Length: ??mm
Cutout Ø: 57mm