Tudor Black Bay GMT 79830RB

The case measures 41mm across, with a 22mm lug width. Case material: Stainless 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.

Automatic, Tudor in-house Cal. MT5652 GMT,

It is rated to 200 meters, about 656 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.

Tudor produced this reference from 2018 to the present day. Production years matter when you are valuing one, because dial, bezel and bracelet details often changed inside a single reference run.

M79830 base reference for the Black Bay GMT; RB = red/blue (Pepsi) bezel. Reading the reference is the fastest way to confirm that a watch is what the seller says it is, before you get anywhere near the movement.

"BB GMT", "Pepsi". Collector nicknames are not official Tudor 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.