Looked fairly deep and couldn't find a match for this one. Both case back and movement are marked M5. My best guess is something along the Minute Man line, only because the lugs are spread out to the side, but I have faith that the panel will shed more insight. Case is 27mm in both width and length, 34 lug tip to tip. Case back has no markings of any kind on the inside. Movement is running strong and it is keeping accurate time. Sorry to keep hitting the panel and members with ID questions, but I really do appriciate it!