====== Sinn 903 St ======
{{wst>image_r|Sinn_903_St|Sinn 903 St}}
{{wst>image_r|Sinn_903_St_Schwarz|Sinn 903 St Black}}
{{wst>image_r|Sinn_903_St_Silber|Sinn 903 St Silver}}
**903 St, 903 St Black** and **903 St Silver** are [[chronograph]]s by [[Sinn]].

Sinn calls this series "Automatic Navigation Chronographs". The peculiarity of the models with the proven [[automatic]] [[chronograph]] movement [[Valjoux 7750]] lies in the integrated [[bezel]] with logarithmic scale division ([[slide rule]] function), as it is also known from the [[Breitling Navitimer]].

In addition, the extremely elaborate preparation of the dials impresses. In pure [[manufacture]] working in a first of more than 30 operations the surface is finished with a [[solar grinding]] (with the black dial variant), as basis for the satin finish. In order to ensure the desired, extremely durable UV resistance, then each dial is also dyed by hand in silver or black with an electrolytic plating method. The result is not only an extremely high-quality appearance with deep, rich luster, but above all absolute color authenticity is guaranteed for many years - and with it a permanent certainty of best readability.


<WRAP ud ud_mod>

**Movement:**
  * Mechanical [[chronograph]] movement [[Valjoux 7750]], 28,800 A/h
  * 28 [[jewels]]
  * [[Automatic]]
  * All brass parts [[rhodinated]], movement parts with [[perlage]], [[rotor]] with [[Geneva stripes]], [[blued]] screws
  * [[Nivarox]] 1 [[hairspring]], [[Glucydur]] [[balance wheel]], Berylium plateau
  * [[Mainspring]] Nivaflex 1, [[Incabloc]] [[shock protection]]
  * [[Shock proof]] according to DIN 8308
  * [[Anti-magnetic]] according to DIN 8309

**Case:**
  * [[Stainless steel]], DIN material number 1.4435, polished/[[satin-finished]]
  * D 41 mm, H 14.5 mm
  * [[Sapphire crystal]] and [[sapphire crystal]] caseback, with [[anti-glare treatment]] on both sides
  * Integrated rotating bezel with logarithmic scale
  * [[Screw-in crown]]
  * [[Waterproof]] to 100 m, low pressure resistant

**Functions:**
  * Hours, minutes, [[small seconds]] with [[hacking seconds]]
  * Date at 4 o'clock 30 minutes
  * [[Chronograph]] 12 hours counter, 30 minutes counter, 60 seconds counter
  * [[Slide rule]] function

**Dial:**
  * Black bzw. silver dial, galvanised with black nickel or silver nickel coating
  * [[Totaliser]]s milled with diamond planing
  * Hands, number 12 and indexes with [[luminous]] coating

**Bracelet: **
  * Black leather strap with [[tang-type buckle]] in polished [[stainless steel]]
  * Optionally available with solid polished gracefully built / [[satin-finished]] [[stainless steel]] bracelet with milled butterfly clasp, band members for length variation

**Warranty:**
  * 2 years
</WRAP>

{{tag>Watch_models Chronographs Sinn_Pilot's_Watch_models Sinn_Instrument_Chronograph_models}}