This one I am not sure where it should be posted. I have 2 in the current configuration of a wristwatch. One complete original Eterna and one parts Eterna. I have 2 more on the way. A Eterna in the full complete odd kit and another complete Zenith.....so what is all this about. I purchased this unusual Zenith Special "Wristwatch" a while back. There was no information to go by so once it arrived I dug into the watch. The first 2 pics are from a few minuets ago and the others are from when I was taking it apart to learn more. The back was cleverly made to thread onto the center post of the watch. It is prevented from turning by a set screw in the smaller hole at 12. With the set screw removed you can remove the adapter. By pressing in on the center post with the adapter partly threaded on you can actually get the watch out of the outer "can". There were then 3 screws on the edge holding the back on the case. So once into the watch I was able to obtain the serial I sent to Zenith SA. More on the result of that shortly. Inside there is a Georges Favre Jacot marked movement. Gilt finish and 15 jewels. The watch is wound by turning the bezel and set by pulling on the bezel until it clicks and then turning in either direction to set. Onve in position you just press down and it clicks back into winding. A few interesting things to note. The setting ins completed by a pinion that goes all the way through the watch next to the smaller cog. There is no indication or evidence that the winding wheels that would have been on the movement were ever installed. No wear to the gilding to indicate any winding by the traditional method. So the results from Zenith.... After a month of waiting I got a phone call from Switzerland. Usually they just email a copy of the cert and info. In this case though they wanted more info. Apparently their records are "odd" when it came to this serial. The movements were made in 1919. They were not shipped until 1936. The GFJ markings were still common for the Russian market as the GFJ name was still very much recognized there. They opted for many years to continue with the name even after the change to Zenith as a brand. The record did not indicate who the delivery was to. They were listed as being sold as complete watches and wristwatches at that. We discussed the dial and they confirmed that the dial is correct but for the German market and they did not believe the watches were shipped to the Germans. Prior to the calls with Zenith I had been hunting others of these down on line. Not easy to do but there were some great fellow collectors willing to talk about their watches. Same dials, movement markings, and design. So the dial was not swapped on by whomever made the adapter. I made sure to relay the serials and descriptions to Zenith who confirmed that they were all recorded the same way. I made sure to pass on any info I go to the collectors that had helped. A few months later my watchmaker happened on 3 watches in a lot he bought. 2 Eterna and one GFJ bezel winds. Sadly the GFJ had a miss matched non Zenith dial on it. The one Eterna had no dial at all and the other Eterna was complete. So knowing that finding a Zenith special dial with no seconds would be difficult I ordered a modern dial to sit in place until I can find a suitable replacement. The watch was in the stainless steel adapter seen below. As to how these started life...the Eterna's helped answer that. I have an unmodified Zenith on the way as well as an Eterna complete in the box. Before you think these must be huge....the diameter is only 40mm across the bezel and 50mm across the original with the holes. The statement was made that these were made to be used in a radio triangulation kit back in WW2. They resided in a box where they were suspended by springs to minimize shocks. I will be able to post more once the one in the box arrives. As to the Eterna and Zenith that don't have boxes I am actually considering a way to mount them as a watch without modification to the original cases.