In view of prices going sky high (sub crowns up for as much as $1000) and zero availability, I have made a mod to a non UG watch that had a similar crown (slightly smaller at 6.5mm instead of 6.7mm) and almost identical profile. Crown requires a new crown tube, it has an inside thread and a spring loaded locking mechanism (like the rolex crown) and should be water proof. It looks great ...

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Looks great, congratulations. If i had one of those, at the time, maybe i hadn't sold my crownless Polerouter Sub...