Now and then I see posts about watches and stuff and I guess it's slightly car-related as every car-magazine I read has lots of advertorials in 'm from TAG-Heuer, Breitling, etc.
Yesterday I bought an old A4C-1 (or ASF-1 as the former is actually written 'АЧС-1' in Russian), this is a 25 jewel (two are on the verge that contacts the balance wheel) 2-day movement and it's rated for all military applications including space. This one was from a MIG (not clear which one, it was mounted in the 23, 25 and 29).
The glass is 72 mm (2.8") in diameter and it's based on Jaeger Le Coultre design.
No, the rear terminals are not for lighting it up, the dial markings and hands are painted with phosphorescient paint so that when a UV cockpit light is shined on them they glow.
The 27 volts are used for an internal heater, as MIGs were capable of getting on heights where temperatures were not that comfortable. It ensures operation even at -60°C (75°F)!
Adding another car-related angle, they were often mounted in Saabs used for rally racing, it even ended up in one used at the Monte Carlo rally.
A friend of mine mounted it in his Healey (It's the thing on the right obviously) and I think I'm willing to find a place for it in my 2002 as well.
I hope I'll end up using my 2002 for some classic-car rally events so I better equip my future navigator with some handy tools.