Description
Sinn 903 St II A
The Sinn 903 St II A represents the continued evolution of one of the most technically accomplished navigation chronographs in modern watchmaking. Defined by its anthracite electroplated dial with refined sunburst decoration, this model balances functional intensity with understated elegance. It remains unmistakably part of the 903 lineage, yet its updated execution demonstrates how Sinn continues to refine proven engineering concepts without compromising their original purpose.
At first glance, the dial reveals the complexity that defines the 903 series. The tricompax layout with galvanically silver-plated sub-dials reinforces its identity as a classic navigation chronograph. The slide-rule bezel with logarithmic scale allows for precise calculations including time, distance, fuel consumption and currency conversion. Far from being decorative, every scale and marking serves a measurable function, maintaining the 903’s status as a true instrument watch.
The anthracite dial is complemented by hybrid ceramic luminous elements used for the applied indices, the numeral 12, and the hour and minute hands. Each luminous element is meticulously attached by hand, ensuring exceptional luminosity and legibility in low light conditions. This use of hybrid ceramic technology reflects Sinn’s dedication to advancing materials science while preserving clarity of design.
Engineering precision is most evident in the directly operable rotating bezel. Thanks to Sinn’s proprietary DSP Technology, the bezel achieves dynamic sealing up to 20 bar while remaining smoothly adjustable from the outer diameter. Achieving this level of water resistance in a chronograph with a slide-rule function demonstrates decades of accumulated expertise in functional case construction.
Inside the stainless steel case, satinised and polished to emphasise its technical character, beats the LJP L110 self-winding column-wheel chronograph movement. Operating at 28,800 semi-oscillations per hour and offering a power reserve of at least 60 hours, it delivers precise, reliable performance. The column-wheel architecture ensures crisp chronograph actuation, while the transparent sapphire case back allows the exquisitely decorated movement to be admired in full detail.
Water-resistant and pressure-resistant to 20 bar, anti-magnetic in accordance with DIN 8309, and low pressure resistant, the Sinn 903 St II A is engineered as a professional instrument. Yet beyond its technical credentials, it remains a study in purposeful design, where functional excellence and aesthetic restraint coexist in perfect balance.
Technical Specifications
Mechanical Movement
- LJP L110
- Self-winding mechanism
- Column wheel chronograph, exquisitely decorated
- 26 bearing jewels
- 28,800 semi-oscillations per hour
- Power reserve: at least 60 hours
- Seconds stop function
- Anti-magnetic as per DIN 8309
Functions
- Hours, minutes, subsidiary seconds
- Date display
- Chronograph
- Bezel with logarithmic scale and slide rule function
Case
- Stainless steel, polished / satinised
- Sapphire crystal glass, anti-reflective on both sides
- Transparent sapphire crystal case back, anti-reflective on interior
- Screw-fastened case back
- Screwable crown
- Water-resistant and pressure-resistant to 20 bar
- Low pressure resistant
- Meets DIN 8310 for water resistance
Dimensions and Weight
- Case diameter: 41.00 mm
- Case thickness: 14.5 mm
- Band lug width: 22 mm
- Weight without strap: 84 gramme
Dial and Hands
- Anthracite electroplated dial with sunburst decoration
- Number “12” and indices made of hybrid ceramic luminous elements, attached by hand
- Hour and minute hands with luminous coating
SINN Technologies
- DSP Technology – dynamic sealing up to 20 bar for directly operable rotating bezels with inner scale
