I've looked over the other threads on here about these and other older 10s watches but I still had a few more questions. I, eventually, would like to have one of each model of the P.S. Bartlett that was made, so I had grabbed the one in the pictures below off of ebay last week. Just a small chip in the dial near 2o'clock, but the movement looks beautiful. I don't have the skills to fully disassemble a movement but it starts right up with a small shake. I also don't have the correct size key to give it a full wind, it seems to be a good bit smaller than size 18's. Could someone tell me what size key this watch would take? Of course, it was movement only as so many of them are. Why are so many, of this size specifically, missing their cases? Low production numbers? Sold off during the Depression or World War's? But if so, why this size? So other than the obvious parts of it needing to be size 10, have the two key holes in the back and also have the correct hole for the movement pin, is there anything else specific I need to look for when buying a case? Besides ebay, would there be any other places I should check for a case like this? Lastly, (I hope I'm allowed to ask this here) roughly how much do these cases sell for when they pop up? I hope that wasn't too many questions for everybody haha! Thanks in advance for the information, it's deeply appreciated.

