So the 38.5 mm fits like a glove. Have owned the 40 mm version before. While beautiful in its own right with slightly more wrist presence, it was a touch too large on my wrist after all
And I really liked it! But at the time I felt I didn't need another watch and thus I didn't buy it. But it left a very long lasting impression and now I feel the need for an 1815 in 40mm, but now they don't make it anymore. Sadly. My wrist is about your s...