The Brellum Duobox 39 Chronometer brings the brand’s automatic chronograph into a smaller 39.5 mm case, with a 48 mm lug-to-lug span. But the domed sapphire crystals bring total thickness to 15.3 mm, so this is a compact-diameter watch rather than a slim one. In Fratello’s November 2024 hands-on review, Michael Stockton called it well-balanced and comfortable; that is his wearing impression, not a guarantee of fit for every wrist.
Does the Duobox 39 wear smaller than Brellum’s larger chronographs?
Its 39.5 mm diameter and 48 mm lug-to-lug measurement make the Duobox 39 more compact across the wrist than Brellum’s preceding 42–43 mm watches. Yet the 15.3 mm overall height, measured over the domed crystals, gives it a substantial profile. Brellum also lists 11.05 mm without the crystals, a figure that describes the case without the raised front and back glass rather than the watch as worn.
Michael Stockton’s Fratello review describes the watch as “perfectly sized” and well-balanced. He also praised the bracelet as thin, comfortable and nicely made. Those are the reviewer’s impressions from his November 15, 2024 hands-on, and the thickness remains an important counterpoint for anyone who prefers a watch that sits close to the wrist.
What are the specifications?
| Specification | Brellum Duobox 39 Chronometer |
|---|---|
| Case | 316L stainless steel |
| Diameter | 39.50 mm |
| Lug to lug | 48 mm |
| Thickness | 15.30 mm including domed sapphire crystals; 11.05 mm without crystals |
| Crystal and caseback | Sapphire front crystal and sapphire display back |
| Water resistance | 100 m |
| Movement | BR-110 automatic chronograph, based on a Lajoux-Perret movement, with column wheel |
| Certification | Brellum states that the movement is COSC-certified |
| Rate and jewels | 28,800 A/h; 26 jewels |
| Power reserve | 60 hours |
| Functions | Hours, minutes, date, small seconds, 30-minute and 12-hour chronograph counters, pulsometer scale |
These dimensions and movement specifications are listed on Brellum’s product page; Fratello’s review independently reports the same case dimensions.
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- COSC Certified Chronometer
- Case Size: 39.00 mm, Band Width: 20 mm, Case Thickness: 10.98 mm
- Automatic movement, 316L solid stainless steel bracelet, Roman dial type, Date
- Water-resistant up to a pressure of 10 bar (100 m / 330 ft): suitable for short periods of recreational swimming and showering, but no diving or snorkeling.
What changed between the launch versions and the current listing?
They are different editions, not simply different names for one unchanged release. Fratello’s 2024 launch coverage shows silver, blue and anthracite dials, with 46 numbered watches in each color. The current Brellum product page lists an ice-blue mother-of-pearl dial limited to 46 pieces worldwide. The page also offers silver, anthracite and blue variants, but its ice-blue MOP edition is the one with a specifically stated current price and availability snapshot.
The included straps also vary by edition. The launch package reviewed by Fratello came with a steel bracelet and black calfskin strap; the current ice-blue MOP listing describes a steel bracelet and white leather strap. The sources do not specify lug width, so they do not establish compatibility with aftermarket straps.
Rank #2
- Movement: Automatic Mido Caliber - Power reserve 80 hours - COSC Certified
- Case Type: Stainless steel and ceramic bezel - Screw-down crown
- Case Size: 43.5mm - Band Width: 22mm - Case Thickness: 14.55mm
- Crystal: Sapphire crystal with double sided anti-reflection treatment
- Strap: Stainless steel bracelet - Folding clasp with diving extension
What does the Duobox 39 cost?
At the time of the current product-page snapshot in 2026, Brellum listed the ice-blue mother-of-pearl edition (SKU DB.CH.946) at CHF 3,190 and marked it available. That price and stock status can change. Brellum notes that non-CHF converted prices are estimates, final charges may vary, and import taxes or customs may apply. Check the product page for the price and availability applicable to your location.
For context only, Fratello reported a 2024 launch price of €3,765 including VAT and shipping for the original dial-color releases. That is dated launch pricing, not a current quote for every variant, and should not be treated as directly comparable to the current CHF listing.
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- Movement: COSC-Certified Automatic Mido Caliber 80 Chronometer SI with silicon balance spring. In addition to its non-magnetic properties, it offers greater precision and improved shock resistance. This caliber ensures exceptional autonomy of up to 80 hours.
- This Swiss-made MIDO timepiece, designed to withstand the extreme pressures of the deep sea, is exceptionally water-resistant to 60 bar (600 m/1968 ft). Equipped with a helium valve, it guarantees safe decompression during extended dives.
- Case Type: Stainless steel with ceramic bezel and Sapphire crystal with double sided anti-reflection treatment - Screw-down crown.
- Case Size: 43.5mm - Band Width: 22mm (Tapered) - Case Thickness: 14.55mm
- Strap: Tapered Stainless steel bracelet - Folding clasp with diving extension
What is the main tradeoff?
The Duobox 39 offers a smaller diameter and shorter lug-to-lug span than Brellum’s prior 42–43 mm watches, alongside a column-wheel automatic chronograph, COSC certification as stated by Brellum, and a 60-hour reserve. Its key compromise is vertical presence: 15.3 mm including the domed crystals is a meaningful height for a watch with a 39.5 mm diameter. Stockton’s favorable fit assessment suggests the proportions worked for him, but wrist shape, cuff clearance and preference for thicker watches will determine whether that balance works for another wearer.
Quick Recap
Best Value
- COSC Certified Chronometer
- Case Size: 39.00 mm, Band Width: 20 mm, Case Thickness: 10.98 mm
- Automatic movement, 316L solid stainless steel bracelet, Roman dial type, Date
- Water-resistant up to a pressure of 10 bar (100 m / 330 ft): suitable for short periods of recreational swimming and showering, but no diving or snorkeling.
Rank #4
- Omega Seamaster Automatic Chronometer Black Dial Men's Watch 210.30.42.20.01.001
Sources
- Brellum: Duobox Chronometer 39 product page — specifications, edition details, price and availability.
- Fratello, Michael Stockton, November 15, 2024 — hands-on observations and launch details.
- Brellum official homepage — the brand’s direct-to-customer approach and owner Sébastien Muller’s statement.
- Brellum strap accessories inquiry page — a contact route for questions about accessories.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
