>>12303168
The clock is part of a WWII German aircraft navigation device.
The Fl number holds the key:
23: Navigational device
889: embedable small clock, to be incerted into recce camera e.g. Rb 50/30 for dateing (on the white center field)/ timing a photo. The clock will be mirrored onto the photo thereby registering a photo.
Details:
Einbauuhr Bo U-bi, Alu-Gehäuse 37 mm mit Heizung
Urofa Cal. 584, Hersteller : Wempe, Hamburg
The electrical contacts on the back are for the heating the clock.
1:25. 11/6, 17, Ration?