A friend decided to cracked open a rare 4S15 cream Alpinist today to see how the gasket that secures the secondary crown looks like.
The curious thing about the Alpinist range of watches is that they are the few 200m WR Seiko watches (but not Diver’s 200m) watches, with a screw down crown. However the secondary crown, located at the 4 o’clock position, which is used to rotate the internal bezel is not screwed down.
Interestingly the internal bezel has teeth on the underside despite it having no clicks whatsoever when rotating. I suppose this is to allow the crown, which probably has its own teeth, to catch on and move the internal bezel along its way.