Aircraft Clock, AChS-1, USSR, Working
This is a very competent example of the mechanical Soviet military aircraft chronograph, type AChS-1. The electrical connection in the back is to power a heater to the instrument, along with the mounting bracket.
There is a helpful description of its multiple functions at http://www.prc68.com/I/8day.html and we won't bother to repeat it here.
Once wound, the clock operates as it should. Its nice to hear a ticking clock once in a while!