The Sinn 903 Collection is a family of navigation watches. Each of the watches would make a reliable travelling companion with their perfect orientation is space and time. All of the 903 watches have the capacity to help the wearer to solve the most important arithmetic functions. The dials of the 903 watches are some of the most difficult to produce, requiring over 30 separate steps due to their complexity. Sinn watches are known for using high-quality movements and materials, and the 903 watches are no exception. The collection contains a variety of dial colours and movements to ensure that the 903 collection contains the perfect timepiece for every collector. 

Core Features of the 903 Collection: 

• The 903 watches are designed to be the perfect travelling companion with their eye-catching dial design and ability to solve mathematical problems. 
• Each watch uses sapphire glass to protect the dial. The glass has anti-reflective treatment on both sides. 
• The watches all have a transparent case back made of sapphire glass that has anti-reflective treatment on the interior. This allows the wearer to observe the movement.
• Each of the watches features a bezel with a logarithmic scale and slide rule function. This aids the wearer in multiplication and division, calculating problems and completing various conversions. 
• All of the watches in the collection are water-resistant and pressure-resistant to 20 bar and meet the technical requirements for waterproofness, as set out in standard DIN 8310. The watches are also resistant to low pressure. This is aided by the screw-fastened case back and winding screwable crown.

Model Specifications 903.091:

• This column wheel chronograph exhibits a dark blue dial with a luminous ivory coating and three sub-dials. 
• The dial also features hour and minute hands made of hybrid ceramic luminous elements. The number “12” and baton indices are made of hybrid ceramic luminous elements as well. 
• A date display features at the 4:30 position. 
• A polished and satinized stainless steel case frames the dial. The case measures 41mm in diameter. 
• The silver-electroplated bezel features a logarithmic scale and a slide rule function. 
• A stainless steel bracelet secures the watch to the wrist.
• The watch is powered by an LJP L110 automatic mechanical movement with at least a 60-hour power reserve. It uses 26 jewels and beats at 28,800 semi-semi-oscillations per hour. The movement also features a seconds stop function and it is anti-magnetic as per DIN 8309.