Is the size of the tachymeter scale. Proportionally it takes up quite a lot of space on the dial. For some reason, paired with that bezel, it's just so pleasing. This is a great example of sheer charm. It would be more practical to relegate the tachymeter to a smaller space, as we are much more often than not looking at the main time display, but I bet that just wouldn't look as good here. What a lovely piece!