Full disclosure, I have not tried on the BB54 yet. However everything Iβve read leads me to believe it will be a much different fitting and wearing watch than my green Seiko. Starting with the obvious, cases size being 3 mm smaller and lug to lug will be a couple mm shorter as well, and also approx 3 mm thinner. The more direct comparison of course with my green Seiko is my BB58 at 39 mm. The BB54 will also be a bit more expensive. But if you donβt care about the larger case size (as compared to 37 mm BB54, yes, the green SPB501 is a must see in this price range! π