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Bremont Supermarine 300M GMT Automatic 40mm Limited Edition Unisex Watch Red
Ref. SM40-GMT-SS-RDBK-B
Sits in Bremont’s upper tier here — more premium than three quarters of the Bremont watches we list, which start at £2,895.
Price range £2,895 to £3,850 across 11 Bremont watches in stock.The "Ember" Red is a boutique-exclusive edition of 200, drawn from Bremont's Supermarine GMT line and named for Iceland's volcanic landscape — a reference carried into the dial's linear red gradient, which deepens toward the centre and reads quite differently under direct light than it does in shade. The move to 904L steel is significant here: the alloy resists corrosion more aggressively than the 316L it replaces and takes a higher polish, which matters on a watch worn in salt water. At 40mm the case is smaller than the Supermarine's traditional proportions, and the 13mm profile sits closer to the wrist than the rating might suggest. The BE-93-2AV runs a Glucydur balance wheel and Anachron spring at 28,800bph with a 50-hour reserve — components chosen for stability under pressure rather than decoration. The bi-colour aluminium bezel insert separates the two time zones visually before you even check the hands, which helps: the GMT hand carries green-emission lume while the main indices and hands glow blue, so the two functions stay distinct in darkness as well as daylight. The caseback is engraved with the world's oceans — a detail that costs nothing to look at once and remains there. The bracelet's infinity-shaped links and tool-free micro-adjust clasp suit a watch that is genuinely meant to be worn in water, where fit matters and a loose bracelet is a nuisance.
- Reference
- SM40-GMT-SS-RDBK-B
- Brand
- Bremont
- Collection
- Supermarine
- Case size
- 40mm
- Case thickness
- 13mm
- Lug width
- 20mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Red
- Crystal
- Sapphire
- Bezel
- Bidirectional rotating
- Movement
- Automatic
- Calibre
- BE-93-2AV
- Functions
- GMT, Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Super-LumiNova
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 48mm
- Power reserve
- 50 hours
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 (7), Stainless Steel Watches (2,613), Automatic Watches (1,479), Sports Watches (679), Dive Watches (488), GMT Watches (197) and Limited Edition Watches (172).
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
- Second time zone for travelling
Bremont Supermarine 300M GMT alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SM40-GMT-SS-RDBK-B | 133300 | 782 |
|---|---|---|---|
| Price | £3,850 | £3,910 | £3,860 |
| Case size | 40mm | 41mm | 42mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Rubber strap | Stainless steel bracelet |
| Power reserve | 50 hours | 38 hours | 42 hours |
| This watch | Closely matched |
|
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 comparedHow long does it run for when it's not worn?
About 50 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
What 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.
Will it fit my wrist?
Lug-to-lug is 48mm, which suits wrists from roughly 16.5cm (6½ inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as unisex, and at this size it suits any wrist that takes the dimensions.
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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