The Navigation Chronograph 903 St B E II Watch

The Watch

Sinn is a watchmaking brand founded in 1961, recognized for a remarkable breadth of technological innovations that set it apart as a truly unique manufacture. Its expertise and craftsmanship shine through every collection - models built to accompany you on every adventure, blending originality, performance, and durability. This prestigious timepiece, The Navigation Chronograph 903 St B E II, was designed for travelers. It features a round case crafted in 316L stainless steel with polished and satin-brushed finishes, a generous 41 mm diameter, 14.5 mm thickness, and a weight of 84 g. The case is topped by a double anti-reflective sapphire crystal for optimal readability of the central indicators. Surrounding the case, a graduated rotating bezel with a logarithmic scale serves as a slide rule. A knurled, screw-down crown in silver sits at 3 o'clock, with two pushers at 2 and 4 o'clock. The screw-down caseback is fitted with a sapphire crystal treated on the inside, offering a stunning view of the movement's mechanics. Compliant with DIN 8310 technical standards, it provides low-pressure resistance and a water resistance of 20 ATM.

The Dial

This watch features a stunning navy blue dial that instantly draws the eye. It pairs effortlessly with any outfit for a clean, refined look. The dial packs multiple functions while maintaining outstanding legibility. Hours are marked by stick indices paired with a single Arabic numeral at 12 o'clock. The hour and minute hands are elegantly shaped in beige with a luminescent coating, while the chronograph's central seconds hand is white with a red tip. The date window sits at an oblique angle at 4:30. The dial also features 3 sub-dials at 3, 6, and 9 o'clock, indicating respectively 30 minutes, 12 hours, and 60 seconds. Around the dial, 3 additional scales work alongside the external bezel to enable a wide range of aeronautical calculations.

The Movement

This watch is powered by an automatic self-winding movement - the Swiss La Joux-Perret L110 caliber. Fitted with 26 jewels, this mechanism beats at 28,800 vibrations per hour for precise timekeeping. It drives the hands, chronograph counters, and the date/day window. It also features a seconds stop (hacking) function and anti-magnetic protection compliant with DIN 8309. Power reserve: 60 hours.

The Strap

This model comes with two straps selectable from the dropdown menu. Both measure 22 mm in lug width.

The first strap is crafted in brown crocodile-embossed calfskin leather for a distinctive look. White stitching adds a striking contrast. Elegant and refined, it makes this watch the perfect companion for city wear. It fastens easily with a 316L stainless steel pin buckle.

The second strap is crafted in satin-finished stainless steel for a classic look. It features brushed and polished links that add an authentic finishing touch. Pair it with any outfit for effortless charm. The clasp is a deployant buckle for easy, precise adjustment.

Water Resistance

With a water resistance rating of 20 atmospheres - equivalent to 200 meters - this model qualifies without hesitation as a dive watch. Our watchmaking experts agree: while this timepiece handles showers, baths, lap swimming, freediving, and recreational scuba diving with ease, it is not designed for extreme deep-sea diving, where pressure would exceed its resistance rating. For professional divers taking on serious depth challenges, we recommend models rated 30 ATM and above. We also advise against operating the pushers or crown while underwater, in order to maintain a perfect seal.