Many thanks - that's really useful.Hi. That's a late 60's or early 70's watch. It was sometime around 1973-ish (give or take a year) that the word "waterproof" was no longer allowed to be used so it has to be before then. It's a manual wind movement inside. If you can have a watchmaker take off the back, there will be a 4 digit number on the inside of the case back which is the reference (model) number and a serial number on the movement. Get us a picture of the movement clear enough to read the serial number and we can tell you what year it was most likely made.