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Bremont Supermarine 300M Date 40mm Mens Watch Brown
Ref. SM40-DT-BI-BR-B
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Stepping up in Bremont's range
The Supermarine line has always been built around serious water use, and this bi-colour variant applies that same brief to a more considered aesthetic. The case is 904L steel — the grade Rolex made famous for its corrosion resistance and polish retention, and an upgrade from the 316L used in earlier Supermarine generations — with 18ct rose gold capping both the knurled bezel and the screw-in crown. The brown aluminium bezel insert carries trapezoid indices that Bremont has deliberately carried through onto the dial itself, where a naval crosshair divides the gradient brown face. It reads as a considered design decision rather than coincidence. At 12mm deep, this sits unusually flat for a rated depth of 300 metres, which means it disappears under a cuff in a way that few dive watches manage. The bracelet uses alternating polished and satin infinity-shaped links in the same 904L steel, with micro-adjustment at the clasp — practical on the wrist in a way that matters when water temperature changes and the fit shifts. The caseback carries an engraved map of the world's oceans, visible only to the owner, which is exactly the right place for something like that.
- Reference
- SM40-DT-BI-BR-B
- Brand
- Bremont
- Collection
- Supermarine
- Case size
- 40mm
- Case thickness
- 12mm
- Lug width
- 20mm
- Case material
- Rose gold
- Case shape
- Round
- Dial
- Brown
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- BE-92AV
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Brown
- Lume
- Super-LumiNova
- Retailer
- Mappin & Webb
Additional specifications
- Gem set
- Yes
Learn more about Bremont
Nick and Giles English founded Bremont in 2002, four years after their father died in a plane crash that Nick survived. All three had restored and flown vintage aircraft together, and the brand that emerged is inseparable from that. The name comes from Antoine Bremont, a French farmer who sheltered the brothers after an emergency landing.
Bremont set out to rebuild British watchmaking, which had effectively ended in the twentieth century. The early watches used Swiss movements in British-designed cases, with the Trip-Tick three-part case construction and a hardened outer barrel treated to over 2000 Vickers.
The military and aviation work is real rather than thematic. Bremont holds contracts with squadrons across the RAF, the US Air Force, and other services, producing issued watches for specific units, and has made watches for Martin-Baker ejection seat survivors — tested to the ejection forces themselves.
The company has also built watches incorporating material from historical objects: oak and copper from HMS Victory, aluminium from the Wright Flyer, and steel from Bletchley Park.
The manufacturing ambition advanced with the opening of a facility in Henley and the release of the ENG300 series in 2021, the first Bremont movement designed and largely made in England. Production is in the low tens of thousands annually.
- 2002
- Nick and Giles English found Bremont.
- 2007
- The first watches ship with the Trip-Tick case.
- 2009
- The Martin-Baker collaboration begins.
- 2021
- The ENG300 becomes the first English-made Bremont calibre.
Also in 7 collections
This watch appears in the Bremont Supermarine range (14), Back in Stock (2,038), Automatic Watches (1,503), Sports Watches (687), Dive Watches (495), Solid Gold Watches (143) and Brown Dial Watches (77).
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- 40mm suits most wrists
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Bremont Supermarine 300M Date alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SM40-DT-BI-BR-B | 133300 | L28394522 |
|---|---|---|---|
| Price | £4,700 | £3,910 | £4,550 |
| Case size | 40mm | 41mm | 43mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Rubber strap | Fabric strap |
| Power reserve | — | 38 hours | 52 hours |
| This watch |
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Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 300m it is rated for swimming, snorkelling and recreational diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedWhat size strap does it take?
20mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Is it a men's or women's watch?
Listed as men's, though at 40mm it sits in the range that suits anyone.
Cheapest place to buy
Mappin & Webb is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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