TUDOR · Black Bay 58
TUDOR Black Bay 58 M7939A1A0NU-0001: specifications and what to check
The smaller, thinner Black Bay: 39mm across and 11.7mm deep, on a five-link bracelet, with the METAS-certified MT5400-U. The proportions are the whole argument for this reference.
Reference M7939A1A0NU-0001 · specifications read from the manufacturer on 2026-09-22 · listed as current
Specifications
As published by TUDOR. A field the manufacturer does not state is left out rather than filled in.
- Case
- 39mm stainless steel case with polished and satin finishes
- Diameter
- 39 mm
- Thickness
- 11.7 mm
- Lug width
- 20 mm
- Water resistance
- Waterproof to 200m (660 ft)
- Crystal
- Domed sapphire crystal
- Bezel
- Unidirectional rotatable bezel in stainless steel with anodised aluminium insert
- Dial
- Matt black, domed, with applied hour markers
- Crown
- Stainless steel screw-down winding crown with the TUDOR rose in relief
- Bracelet
- 5-link stainless steel bracelet with polished and satin finishes
- Clasp
- TUDOR "T-fit" clasp
Movement
- Calibre
- Manufacture Calibre MT5400-U
- Type
- Self-winding mechanical movement with bidirectional rotor system
- Power reserve
- 65-hour power reserve
- Certification
- COSC and METAS certified
What to check before you buy
- Verify the calibre is MT5400-U rather than an earlier MT5402. The Master Chronometer version is a different movement, and the two are easy to conflate in a listing written from memory.
- Inspect the anodised aluminium bezel insert closely. Aluminium marks in a way ceramic does not, and insert condition is one of the larger swings in desirability on this reference.
- Work the five-link bracelet's T-fit clasp through its adjustment range, and check the links for stretch at the pins.
- Compare the thickness against the seller's description. At 11.7mm this genuinely is the slim one in the family, which is precisely why buyers seek it out — and why a swapped caseback matters.
- Confirm the 20mm lug width before quoting a strap change. It differs from the 41mm Black Bay, and assuming they share a size is a common and avoidable error.
Why this reference exists
The Black Bay 58 answers a complaint about its larger sibling. Where the 41mm Black Bay stands 13.6mm deep, this one measures 11.7mm across a 39mm case — and those two figures are the entire commercial argument for it.
For a dealer that matters because the demand here is specific rather than general. Someone looking for a 58 usually wants the proportions, not the name, and will not accept the bigger case as a substitute. Cross-selling between them rarely works.
The calibre question
This carries the MT5400-U, the METAS-certified Master Chronometer version. The earlier generation of this collection used a different manufacture calibre, and listings — especially ones written quickly — routinely blur the two.
Open the papers, read the calibre, and match it to the reference. A description is not evidence, and on a family this long-running the movement is the thing most often misstated.
Aluminium, not ceramic
The bezel insert here is anodised aluminium. That is a deliberate nod to the vintage references the design draws on, and it behaves accordingly: it scratches, it fades, and it shows a knock in a way a ceramic insert never will.
Insert condition therefore carries more weight on this reference than on watches that use ceramic. Inspect it under angled light before agreeing anything, and describe it honestly when you sell — the condition report exists for exactly this kind of component-level detail.
Small things that cost money
20mm lugs, not the 21mm of the 41mm Black Bay. Quote a strap on the assumption they match and you will be wrong.
65 hours of reserve, five fewer than the larger reference — immaterial in use, but worth stating correctly if you are writing the listing.
Price references like this, faster
What a reference is worth at intake, what to check before you buy it, and where it sells best. Free guides for dealers.
Sources
Not affiliated with TUDOR. Specifications are read from the manufacturer's own published documentation on the date shown and may change; the manufacturer's current documentation governs.