Tudor Black Bay 58 18K M79018V

Getting to Know Tudor

Tudor sits in a specific place in the modern Swiss watch market: priced below the upper luxury tier and built around the brand's own Manufacture Caliber movement program rather than third party supply. The current lineup spans the Black Bay and Pelagos dive collections, the Ranger field watch, the Royal, the 1926, the new 2026 Monarch, plus a chronograph and GMT family that has grown sharply over the last 18 months.

How a Tudor Reference Number Works

A current Tudor reference reads as M, followed by 4 or more digits identifying the model family, then one or more letters keying the variant, then a hyphen and a 4 digit suffix that decodes dial and strap. The leading family digits are the fastest tell: 79 prefixes a Black Bay, 25 a Pelagos, 28 a Ranger, and 56 a Royal or 1926.

Reference M79610N-0001 reads as a Black Bay 58 in black. M79830RB-0001 is the Black Bay GMT in the red and blue Pepsi configuration. M7939G1A0NRU-0001 is the 2024 Black Bay 58 GMT. M25600TN-0001 is a Pelagos 42 in titanium. M2543C1A7NU-0001 is the Pelagos Ultra. M79310N-0001 is the new 2026 Black Bay Chrono 39 with the yellow dial.

The letter inside the variant tracks bezel or dial color in a rough convention: N most often signals black, B blue, and R burgundy or red, with combinations like RB pulling both colors of a two tone bezel into the reference itself. The trailing 4 digits after the hyphen separate dial and strap configurations on the same case. The reference and the caliber name are engraved on the caseback of every current Tudor.

What the Specifications Actually Tell You

Movement and Caliber

Every Tudor in current standard production runs on a Manufacture Caliber, the MT series the brand started developing in 2015. The MT prefix stands for Manufacture Tudor; the trailing digits key the variant; a U suffix flags calibers that have passed METAS Master Chronometer certification on top of the standard COSC chronometer rating.

Caliber MT5400 and the upgraded MT5400-U power the current Black Bay 58 with a 70 hour reserve. MT5602 runs the time only Black Bay 41 and the Pelagos FXD. MT5612 sits in the Pelagos 42 with a date and the same 70 hour reserve. MT5450-U is the GMT caliber built for the 2024 Black Bay 58 GMT, integrated rather than modular, with a 65 hour reserve and METAS certification. MT5652-U powers the full size Black Bay GMT and the Pelagos FXD GMT. MT5813 is the chronograph movement in the Black Bay Chrono and the Pelagos FXD Chrono, derived from the Breitling B01 with a column wheel, vertical clutch, and Tudor finishing.

All Manufacture Calibers share a variable inertia balance held by a traversing bridge anchored at two points, a silicon hairspring for magnetic resistance, and a 4 Hz beat rate. Every current Tudor carries a 5 year transferable guarantee with no registration required.

The Dial

The defining Tudor dial signature is the snowflake hand, the broad angular hour hand whose head widens into the silhouette carried through every Tudor diver since the Marine Nationale references of the 1970s. It is what distinguishes a Tudor diver from a Rolex Submariner at any distance, and it appears across the entire current Black Bay and Pelagos catalog. The Ranger uses a pointed hour hand to fit its field watch role, and the Royal and 1926 take a polished baton handset for a dressier read.

Dial finishes vary by line. The Black Bay 58 runs a satin black or burgundy with applied gilt indices for the vintage look. The Black Bay 58 GMT pairs that gilt against a glossy black and burgundy bezel. The Pelagos uses a matte black or matte blue with square indices and a depth rating printed in red. The Pelagos Ultra scales the whole layout up with thicker hands and larger markers for legibility at depth, with a two color luminescence scheme: green on the minute hand and pip, blue on the hour markers. Super-LumiNova is applied across the catalog in white or X1 grade.

Case Material and Size

Stainless steel is the standard across the Black Bay and Royal lines, with bronze used on the Black Bay Bronze and 18 karat yellow gold on the Black Bay 58 18K. Titanium is the dedicated Pelagos material, in Grade 2 for the standard Pelagos and a mix of Grade 5 and Grade 2 on the Pelagos Ultra where strength and weight both matter. The Pelagos FXD Chrono uses a carbon composite case, a first for Tudor when it launched in 2023.

Case sizes by line: the Black Bay 54 at 37 millimeters, the Black Bay 58 and Black Bay 58 GMT at 39, the Black Bay 41 and Black Bay GMT at 41, the Black Bay 68 and Black Bay Bronze at 43. The Pelagos sits at 39 and 42, the Pelagos FXD at 42, the Pelagos FXD Chrono at 43, and the Pelagos Ultra at 43. The Ranger at 39, the Royal at 30, 36, and 40 in the 2026 refresh, the 1926 at 28, 36, 39, and 41, and the new Monarch at 39.

Water Resistance and Crystal

The Pelagos line is the brand's serious dive tool. The standard Pelagos 39 and Pelagos 42 carry 500 meters of water resistance, the Pelagos FXD 200 meters per the original French Navy spec it was built around, and the Pelagos Ultra 1,000 meters with a compact helium escape valve at 10 o'clock for saturation diving. The Black Bay diving references all hold 200 meters across the 41, 58, 54, 68, GMT, Pro, Chrono, and Bronze variants, named after the 1958 reference 7924 that first achieved that rating for Tudor.

Crystals are sapphire across the catalog. The Black Bay carries the line's signature domed profile that wraps the dial edge for the vintage look, the Pelagos uses a flatter sapphire to fit its tool watch brief, and the Pelagos Ultra adds antireflective treatment for legibility at depth. Casebacks are solid steel or titanium on most current production references, with sapphire casebacks reserved for the Black Bay 58 18K and a handful of limited editions.

Telling the Collections Apart

Black Bay 41

The original 41 millimeter Black Bay platform, in production since 2012 and now running the MT5602 caliber with 200 meters of water resistance and a snowflake handset. Offered in black, blue, and burgundy bezel configurations on a riveted three link bracelet, a five link, a leather strap, or a fabric strap, with the steel and gold Black Bay S&G and the Black Bay One sitting alongside on the same case.

Black Bay 58

The 39 millimeter version, named for the 1958 reference 7924 that brought 200 meter water resistance to Tudor. The 2026 refresh slimmed the case to 11.7 millimeters thick and brought METAS certification through the MT5400-U caliber, with black or burgundy dial configurations on a rivet style three link bracelet, a five link, rubber, or fabric, all with the T-fit micro adjust clasp. The Black Bay 58 18K is the solid yellow gold variant with an open caseback over the same caliber.

Black Bay 58 GMT

A 39 millimeter GMT introduced in 2024, the first Black Bay 58 with a second time zone. The Manufacture Caliber MT5450-U is METAS certified with an integrated GMT function built into the movement architecture rather than added as a module, running 65 hours of reserve. The bidirectional bezel carries the black and burgundy Coke insert with subtly curved gilt numerals, paired with a satin black dial, the snowflake handset, and a lollipop seconds hand drawn from the brand's early divers.

Black Bay 54 and Black Bay 68

The two size variants of the Black Bay platform. The Black Bay 54 is 37 millimeters in steel, dialed to vintage Tudor Submariner proportions, with the MT5400 caliber and 200 meters of water resistance. The Black Bay 68 is 43 millimeters in steel, introduced at Watches and Wonders 2025 for buyers who want the same DNA in a larger case.

Black Bay GMT and Black Bay Pro

The 41 millimeter Black Bay GMT carries the red and blue Pepsi bezel, the MT5652-U Master Chronometer caliber, 200 meters of water resistance, and 70 hours of reserve. The Black Bay Pro is the 39 millimeter version with a fixed 24 hour bezel rather than a rotating one, paired with the same MT5652 caliber in a flatter case that wears closer to a field watch with a second time zone added.

Black Bay Chrono

The chronograph. Offered at 41 millimeters with the MT5813 caliber, a two register layout with counters at 3 and 9 and a date at 6. The new 2026 Black Bay Chrono 39 brings the same caliber into a slimmer 39 millimeter steel case at 13.1 millimeters thick with a yellow dial. The Black Bay Chrono Carbon 26 is a 2026 limited release of 2,026 pieces in a carbon fiber case with yellow accents tied to Tudor's Formula 1 partnership.

Pelagos

The titanium dive line. The Pelagos 42 is the 42 millimeter standard in Grade 2 titanium with 500 meters of water resistance, helium escape valve, and the MT5612 caliber. The Pelagos 39 is the smaller version of the same brief, with the MT5400 caliber and 200 meters of water resistance for buyers who want the Pelagos design language in a more wearable case. The Pelagos Ultra is the 43 millimeter deep diver introduced at Watches and Wonders 2024 with 1,000 meters of water resistance, METAS certification, and the scaled up dial for legibility at depth.

Pelagos FXD

The fixed lug military line, developed with the French Navy's Marine Nationale combat divers. The 42 millimeter titanium case carries fixed strap bars at the lugs (the FXD in the name), a bidirectional dive bezel inverted from the standard Pelagos format, and the MT5602 caliber, rated to 200 meters. The Pelagos FXD GMT adds the MT5652-U caliber in the same case for a second time zone. The Pelagos FXD Chrono is the chronograph variant in a 43 millimeter carbon composite case with the MT5813.

Ranger

The 39 millimeter field watch reintroduced in 2022 for the 70th anniversary of the British North Greenland Expedition. Steel case, brushed finish, MT5402 caliber, 100 meters of water resistance, and a pared back dial layout with painted Arabic numerals and an hour hand silhouette drawn from the original Oyster Prince references.

Royal

The integrated bracelet line, redesigned for 2026 with a new in house chronometer movement and refined sizing. Now offered at 30, 36, and 40 millimeters, with the 40 carrying a day display at 12 alongside the date at 3 o'clock and a fluted bezel that nods to the engine turned pattern from the original 2020 release.

1926

The entry point into the brand. A more traditional dress watch offered at 28, 36, 39, and 41 millimeters in steel or two tone, with a smooth bezel, applied indices, and a Sellita based caliber rather than the Manufacture series, named for the year the Tudor trademark was first registered.

Monarch

The new line introduced at Watches and Wonders 2026. A vintage styled three hand watch at 39 millimeters with a California dial (Roman numerals across the top half of the dial and Arabic across the bottom), a pseudo integrated bracelet, and the most finely finished automatic movement Tudor has put into production to date.

Buying Your Tudor from Grand Caliber

Everything on this page, from the reference to the condition, is something we confirm before a watch is ever listed. Grand Caliber is an independent dealer in Uptown Dallas, and every Tudor we sell is authenticated in house and priced openly so you can see the real market value before you decide. If you want to talk through a specific piece or are hunting a reference we do not currently have, you can reach us at 214-225-7198 or info@grandcaliber.com, or browse the full Tudor collection online.

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