Up for sale is a Northern Airborne Intervox  AA80-020 4-Place Intercom. Technical info is as follows:

P/N:  3230015-3

S/N: 21001

MODS: None

Volts: 13.75 27.5 VDC

The unit was in working condition when removed. Missing knobs. If you have any questions, please feel free to ask! Happy buying!