The diameter is part of the equation, but not the only part. In my personal opinion, a dress watch should never be more than 40mm. But, you can get away with a larger diameter if the lugs don't jut out beyond the edge of your wrist. I did notice that this watch has quite long lugs. Combine that with the 43mm diameter, and I think they've sized out most gents with smaller wrists. I do think this is a very nice looking watch, but they should definitely have an option for a smaller size. And they also get a red mark for the 21mm lug width.