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Nomos Glashütte Tetra Duo 27mm Watch
Ref. 405
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Stepping up in Nomos Glashütte's range
The Tetra began as a Bauhaus square in the earliest days of post-reunification Glashütte, and the Duo variant strips it further still — no seconds sub-dial, just two gilt hands on a galvanised white-silver dial. That decision to remove rather than add is very much in the spirit of the original, and the DUW 4001 Duo that makes it possible is worth understanding: at 2.6mm tall it is among the thinnest movements NOMOS has made, built in-house and regulated by the proprietary Swing System escapement. The Duo line arrived in 2019 with an earlier calibre; the current movement extends the power reserve to 53 hours and raises the water resistance from 3 to 5 atm — a quiet but meaningful upgrade beneath an unchanged face. At 27.5mm the case is genuinely small, and 6.1mm thin, with double-stepped lugs that taper to an 18mm width. On a slender wrist it lies almost flush, the square outline sitting flat rather than proud. The golden hands catch warmth against the silver dial in a way that reads as considered rather than decorative, and the beige velour leather softens the geometry at the wrist in a way a polished bracelet would not.
- Reference
- 405
- Brand
- Nomos Glashütte
- Collection
- Tetra
- Case size
- 27.5mm
- Case thickness
- 6.1mm
- Lug width
- 18mm
- Case material
- Stainless steel
- Case shape
- Square
- Dial
- Silver
- Crystal
- Sapphire
- Movement
- Manual
- Calibre
- DUW 4001 Duo
- Functions
- Small seconds
- Water resistance
- 50m
- Bracelet / strap
- Leather strap
- Strap colour
- Beige
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 38.5mm
- Power reserve
- 53 hours
Learn more about Nomos Glashütte
Roland Schwertner, a photographer and computer technician from Düsseldorf with no watchmaking background, registered Nomos in Glashütte in January 1990 — two months after the Berlin Wall fell and before German reunification was complete. The town's watchmaking infrastructure had been state-owned for four decades and was suddenly available.
The design language was settled from the start and has barely moved: Bauhaus in the strict sense, drawing on the Dessau school's functionalism. Sans-serif numerals, no applied ornament, no unnecessary line, and dial layouts where every element earns its place. The Tangente, one of the first models, remains the flagship and looks the same today.
The technical ambition came later and was considerable for a company of its size. Nomos moved from modified Swiss ébauches to its own Alpha calibre, then to the DUW family, and in 2014 introduced the swing system — a proprietary escapement with an in-house hairspring, the component almost no independent manufacturer makes. Fewer than a dozen companies worldwide produce their own hairsprings.
The house is still independent, still based in a converted railway station in Glashütte, with design offices in Berlin. It occupies unusual territory: in-house movements and German finishing at prices closer to Swiss mid-range brands using bought-in calibres, which has made it the most common entry point into serious German watchmaking.
- 1990
- Roland Schwertner founds Nomos in Glashütte.
- 1992
- The Tangente launches and defines the house style.
- 2005
- Production shifts to in-house movements.
- 2014
- The swing system escapement with in-house hairspring is introduced.
Also in 6 collections
This watch appears in Stainless Steel Watches (3,355), Watches Under 37mm (1,771), Women's Watches (1,676), Leather Strap Watches (1,083), Silver Dial Watches (743) and Dress Watches (548).
What the specifications mean
A slim watch on leather, made for wearing with a shirt.
Strengths
- 27.5mm wears small and slips under any cuff
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
- Sits in the lower half of Nomos Glashütte's range as we list it
Worth knowing
- 50m suits rain and handwashing, not swimming
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Showering yes, swimming no. 50m covers splashes and brief immersion, but a swimming stroke generates well above the pressure that figure describes.
Will the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Does it need a battery?
No. It is hand-wound, so it needs winding every day or two but never a battery.
How long does it run for when it's not worn?
About 53 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
What size strap does it take?
18mm. 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 38.5mm, which suits wrists from roughly 15cm (6 inches) upward.
Lug-to-lug decides fit more than case diameter does.
Is it a men's or women's watch?
Listed as women's.
Cheapest place to buy
Mappin & Webb is the only UK retailer we track stocking this reference new, at £1,660. There is nothing to compare it against today.
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