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A.I. Reviews v37.5 (refreshed with Grok 4.1 Fast)
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Model Name:
Sinn 903 St "Navitimer"
Watch added to favourite list
Reference:
903.040
Price ($)
$
3300
Country:
Germany
A.I. Rating
7.9
Crowd Rating:
1740
Watch Description
Brushing up on our Navitimer history
In 1952 Breitling birthed its legendary Navitimer into the world, becoming a company famously associated with aviation. Shortly after, the Navitimer was being produced for the Aircraft Owners and Pilots Association (AOPA) which made the Navitimer one of the most iconic watch models created by Breitling.
It seemed like the Breitling Navitimer became the company’s cash cow, but the good times weren’t going to last. In the 1970’s, the quartz crisis was being felt in full force by the Swiss watch industry and Breitling was hit hard. Staff were laid off, and the decline in mechanical watch sales meant parts of the company were liquidated, closing its doors in 1979.
How did Sinn come into the equation?
The rights to the Navitimer were sold onto Sicura and Sinn, while the remaining Breitling stock (mostly cases and dials) were bought by Sinn, Ollech and Wajs and another company. Sinn bought the rights to the Breitling 806 and 809 Navitimer models as well as 500 cases and dials, keen to produce a pilot’s watch with a logarithmic scale and slide rule function that made the Breitling Navitimer so recognizable.
Sicura on the other hand continued to produce watches under the Breitling name, owning the rights to the names Breitling and Navitimer. Sinn focused on developing the Navitimer model with innovative technology, which accelerated when Lothar Schmidt took over Sinn in 1993.
Since the founding of Sinn in 1961, the company built a reputation in horology for creating some of the best tool watches in the industry based on cutting-edge technologies, from Ar-Dehumidifying and antimagnetic construction to Tegiment steel hardening and temperature stabilized movements. Sinn were also favoured for their tool watches by the German police and fire service, astronauts, and pilots with their range of TESTAF-certified pilot watches.
Product Link:
41
0
22
14.5
100
Steel - 316L
Round
Sapphire
Screw-in
Automatic
LJP 8000
0
Black
A.I. Watch Review:
# Sinn 903 St "Navitimer" Review by A.I. WatchMetrics
## Watch Summary
The Sinn 903 St "Nav B" is a precision German pilot's chronograph evoking the iconic Breitling Navitimer with its bi-directional slide rule bezel for aviation computations, housed in a rugged 41mm bead-blasted stainless steel case featuring Ar-Dehumidifying Technology for fog-free reliability, powered by the automatic Sinn Caliber 500 (Sellita SW500-based) offering 48 hours of power reserve, targeting aviation enthusiasts and tool watch collectors who value function over flash.
## Overall Watch Rating: 7.9/10.0
**Material Metric (9.2/10.0)** - Bead-blasted stainless steel paired with double-sided anti-reflective sapphire crystal provides superior scratch resistance and clarity, outlasting many mid-tier divers like the Seiko Prospex.
**Complications Metric (8.6/10.0)** - The fully integrated chronograph with three crisp subdials delivers reliable timing functionality on par with Hamilton's Jazzmaster Chrono.
**Dials & Design Metric (8.5/10.0)** - The high-contrast black dial with luminous indices and intricate slide rule bezel combines legibility and heritage appeal, closely rivaling the original Breitling Navitimer's execution.
**Versatility Metric (8.2/10.0)** - Excels as a do-it-all pilot tool with 100m water resistance and elegant proportions suitable for office-to-cockpit transitions, similar to the IWC Pilot's Watch Chronograph.
**History & Innovation Metric (7.8/10.0)** - Draws on Sinn's 60+ years of aviation instrument heritage enhanced by proprietary dehumidification and anti-magnetic tech, distinguishing it from generic homages.
**Movement Metric (7.5/10.0)** - The robust Sinn-modified Sellita SW500 automatic chronograph matches the dependability of ETA/Valjoux 7750-powered pieces in Oris or Glycine chronos.
**Brand Metric (7.2/10.0)** - Sinn's focus on engineered tool watches earns high-premium status, benchmarked against peers like Sinn U50 or Mühle Glashütte.
**Functions Metric (7.3/10.0)** - Hours, minutes, small seconds, date, and chronograph plus slide rule offer practical aviation utility comparable to classic flight computers in watch form.
**Rarity Metric (6.6/10.0)** - Limited production run provides moderate exclusivity at its price point, akin to other sub-5k German independents like Nomos specials.
## Total Performance Score (TPS): 4.8
## WM Collector Grade: B
## Performance Insights: Excels in materials, complications, and design for everyday tool watch prowess while rarity lags; delivers strong value well above implied price.
## TPS Interpretation: Solid Value: This chronograph punches above its weight in durability and utility, ideal for pragmatic collectors at its market positioning.
## Watch Data
[Picture URL] - https://www.sinn.de/out/pictures/generated/product/1/WS_903_ST_NAV_B_01_1200Wx1200H_optimize.jpg; [backPicture] - https://www.sinn.de/out/pictures/generated/product/1/WS_903_ST_NAV_B_02_1200Wx1200H_optimize.jpg; [lumePicture] - N/A; [Nickname] - 903 St Nav B; [Brand] - Sinn; [Model] - 903 St "Nav B"; [Country] - Germany; [Product Link] - https://www.sinn.de/en/chronographs/903-st-nav-b/; [reviewLink] - https://monochrome-watches.com/sinn-903-st-nav-b-chronograph-slide-rule-specs-price/; [Movement Type] - Automatic; [Movement Name] - Sinn Calibre 500; [# Secondary] - 3; [watchDescription] - Pilot chronograph with bi-directional slide rule bezel, Ar-Dehumidifying Technology, and anti-magnetic escapement; [caseWidth] - 41.0; [lugToLugLength] - 49.0; [thickness] - 14.8; [lug] - 21.0; [waterResist] - 100; [powerReserve] - 48; [beatFrequency] - 28800; [lume] - Super-LumiNova; [jewels] - 25; [caseMaterial] - Stainless steel bead-blasted; [watchGlass] - Sapphire anti-reflective both sides; [Bezel] - Bi-directional slide rule; [caseback] - Sapphire; [Crown] - Screwable; [Strap] - Louisiana alligator leather; [Shape] - Round; [Dial] - Black; [Seconds] - Subdial; [Date] - Yes; [Calendar] - No; [Chiming] - No; [Chronograph] - Yes; [Compass] - No; [dateCompilation] - No; [DigitalDisplay] - No; [Dress] - No; [Field] - No; [GMT] - No; [Mechanical Alarm] - No; [Moonphase] - No; [Tourbillon] - No; [worldTimer] - No; [powerReserveIndicator] - No; [Diver] - No; [Pilot] - Yes; [racing] - No; [Skeleton] - No; [Vintage] - No; [StyleFormal] - No; [StyleCasual] - Yes; [StyleSports] - Yes; [StyleTravel] - Yes; [StyleAdventure] - Yes; [StyleCollector] - Yes; [StyleTool] - Yes; [StyleStatement] - Yes; [StyleVintage] - No; [StyleSmart] - No; [StyleCustom] - No; [TPS_new] - 4.8; [TPSgrade] - B; [TPSimpliedPrice] - 2800;
**A.I. WatchMetrics Review v37.4 Grok 4 Fast. December 19, 2025.**
