Seiko Prospex SBDX017

The case measures 44.3mm across and 15.4mm thick, with a 20mm lug width. Case material: Steel. Case size alone is a poor guide to how a watch wears; lug-to-lug length and how the bracelet drops off the case matter more, which is why we suggest trying one on before you commit.

Caliber 8L35. Power reserve is 50 hours. It beats at 28,800 vph. The movement uses 26 jewels.

It is rated to 300 meters, about 984 feet. That is a diving rating: it is built for scuba use, not just for getting wet. One caution that applies to every watch on this page: a water resistance figure describes a new watch with fresh gaskets. On a piece that is years past its last service, treat the rating as unknown until it has been pressure tested.

Prospex Marinemaster 300. Collector nicknames are not official Seiko names, but they are what people actually search for and what they are called across a showroom.

Yes. We buy this reference outright, and we lend against it if you would rather keep it. We are a family-owned San Diego buyer established in 2006, our appraisers are GIA-trained, and the appraisal is complimentary with no obligation to sell. You can bring it to our Gaslamp showroom at 907 Sixth Ave or start online. If you are looking to buy this reference instead, tell us and we will let you know when one comes in.