Seiko & Citizen Watch Forum Message Archive

According to Mr. Tokunaga's description, the "Professional" 200m diver has some special structural reinforcements -- like the L-shape gaskets, a screw-down crystal retaining ring, a reinforced (thick) crown design, etc. I think these are a little different from the ordinary quartz or auto models.

When I took off the bezel, I noticed that the design is indeed different from the ordinary auto divers whose crystal is basically pressed down on the case and glued against the gasket. I think the screw-down crystal retaining ring adds a bit of protection against the intrusion of helium into the case when saturation diving and perhaps against the crystal popping loose ??? (and I'm just purely guessing on this, so please don't believe me!).

I haven't seen what the inside looks like, so I don't know what other structural differences there are between the "Professional" model and the ordinary quartz or auto diver.

I'll try to take a pic of the crystal retaining ring tomorrow to show everyone a bit of what Mr. Tokunaga is talking about.

This Pro diver uses the cal. 7C43 movement. If I understand Mr. Tokunaga correctly, this is a close relative of the 7C46 movement used in the Prospex 300m & 1000m shrouded divers. (I'm not familiar with vintage quartz divers. What movement does your 1978 quartz diver use?)

-Kevin