San MartinSN0138-GB
Homage to the Tudor Black Bay 54
about$328
Regular price at the brand's own website, checked 31 Oct 2026. Marketplace prices change often.
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The San Martin SN0138 37 mm Diver is a homage to the Tudor Black Bay 54, with the same 37 mm case size. It uses an automatic movement and is water resistant to 200 m. Its Resemblance Score is 79 out of 100. It costs about $328 at the official store.
Side by side with the original
Compared with reference M79000N. Values marked ≈ are estimates, such as a reviewer's measurement.
| Spec | SN0138-GB | Black Bay 54 (M79000N) | Difference |
|---|---|---|---|
| Case diameter | 37 mm | 37 mm | same |
| Lug-to-lug | 45.8 mm | ≈ 46 mm | −0.2 mm |
| Thickness | 12.7 mm | 11.25 mm | +1.45 mm |
| Lug width | Not published | ≈ 20 mm | Can't compare |
| Water resistance | 200 m | 200 m | |
| Movement | Automatic, ST2130 | Automatic, MT5400 | |
| Power reserve | Not published | 70 h | |
| Crystal | Sapphire, aR coating | Sapphire | |
| Bezel | 120-click unidirectional, bead-blasted, Aluminium | Unidirectional, 60 clicks, steel, Black anodised aluminium, five-minute markers only | |
| Case material | 316L stainless steel | Stainless steel | |
| Lume | C3 green or BGW-X1 blue (hands and markers) | Super-LumiNova | |
| Bracelet | Solid 316L stainless steel bracelet, 20 mm x 16 mm | Steel, three-link, rivet-style | |
| Weight | 147 g | Not published |
- ≈ Black Bay 54, Lug-to-lug: median of 3 agreeing independent measurements (46 mm); the maker does not publish it.
- ≈ Black Bay 54, Lug width: median of 2 agreeing independent measurements (20 mm); the maker does not publish it.
The original
Tudor
Black Bay 54
Reference M79000N, black bay 54, 37 mm, steel bracelet
- Case
- 37 mm
- Lug-to-lug
- ≈ 46 mm
- Thickness
- 11.25 mm
- Water resistance
- 200 m
- Movement
- Automatic, MT5400
- List price
- $4,725
Why it scores 79
Proportions and movement are computed from specs. Design details and functions are judged from the brand's official images. How we score
Proportions26 / 30
- Case diameter12 / 12Same size
- Lug-to-lug7.4 / 80.2 mm apart
- Thickness3.1 / 61.4 mm apart
- Lug width0 / 4Not published, left out
Design signatures25 / 40
- Snowflake hour hand, pencil minute hand and lollipop seconds hand5 / 10Snowflake-style hour hand and a seconds hand with a lume dot near the centre; the minute hand is a plain sword, not a pencil hand, and the seconds tip is not a lollipop.
- Bezel insert with only five-minute markers4.5 / 9Unidirectional bead-blasted insert with five-minute ticks, but it also carries numerals at 10 to 50, where the original shows only markers.
- Small crown sitting flush with the case, no crown guards7 / 7Small screw-down crown close to the case with no crown guards.
- Rivet-style steel bracelet3 / 6Brushed three-link bracelet with no visible rivets.
- Domed glossy black dial with applied round markers and gilt print2.5 / 5Matte dial with applied round plots and a triangle at 12; gilt-toned print only on the black-and-gold option, other options use white or coloured print.
- Dateless dial3 / 3Dateless dial.
Functions and materials18 / 20
- Complications8 / 8Time only, no date, as on the original.
- Bezel action2 / 4Unidirectional bezel as on the original, but 120 clicks against the original's 60.
- Case and bezel materials4 / 4Steel case with an aluminium bezel insert, as on the original.
- Crystal shape and date window4 / 4Sapphire with no date window or cyclops, as on the original.
Movement type10 / 10
- Movement type10 / 10Same movement type.
What reviewers and owners say
Reviewers
From 2 reviews we read or watched.
Reviewers who handled the ST2130 version liked the compact 37 mm case and the 45.6 to 45.8 mm lug to lug, the finishing, the strong lume, a bezel with firm action and little backplay, and the screw-link bracelet with the new on-the-fly clasp. Both said the ST2130 gives a smoother sweep than the earlier NH35, both noted the ghost date position on a dateless watch, and both noted that the price rose over the earlier version (one puts the earlier price at roughly two thirds of the current one). They differed on thickness: one called 12.7 mm chunky for a 37 mm watch given the thinner movement, while the other measured about 12.6 mm, found it slimmer than the NH35 version and the watch comfortable. One reviewer found reflections on the crystal distracting, the other had no complaint about it. One reviewer noted the crown needs more force than expected to pull to the time-setting position.
Good
- Compact 37 mm case and 45.8 mm lug to lug
- ST2130 high-beat movement
- On-the-fly clasp
- Strong lume
- Ten dial colours
Less good
- 12.7 mm thick for a 37 mm watch (one reviewer)
- Ghost date position on a dateless watch
- Price is higher than the earlier version
- Crystal reflections noted by one reviewer
Versions and colours
- Retro Matte BlackIts own colourway, not on the originalabout $328
- Matte BlueIts own colourway, not on the originalabout $328
- Matte GreenIts own colourway, not on the originalabout $328
- Matte PurpleIts own colourway, not on the originalabout $328
- Matte BlackIts own colourway, not on the originalabout $328
- Matte RedIts own colourway, not on the originalabout $328
- Brown WaffleIts own colourway, not on the originalabout $328
- Gradient BlueIts own colourway, not on the originalabout $328
- Gradient RedIts own colourway, not on the originalabout $328
- Gradient BlackIts own colourway, not on the originalabout $328
Earlier versions
- Earlier version (NH35): Earlier SN0138 had an NH35 and an earlier clasp, and sold for roughly two thirds of the current price (reviewer remark); the current page lists the ST2130 and an on-the-fly clasp. One reviewer measured the NH35 version at about 12.9 mm thick, against about 12.6 mm for the ST2130 (ydhdbkiFuek 07:01).
Compare
Sources
Checked 31 Oct 2026. Every figure on this page comes from one of these pages.