Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap

SKU: SI-159

Watch Brand: Sinn

Sinn North America


New Release

Fully Tegimented midsize diver's watch with quartz movement and oil filled case
• Watch diameter (mm): 41.0
• Watch height (mm): 11.8
• Lug width (mm): 20
• Lug to lug (mm): 47
• Weight - head only (grams): 72
• Water resistance: 5,000 meters
• Case back: Solid
• Case finish: Black DLC steel
• Case metal: Tegimented hardened DLC steel
• Dial color: Black
• Front crystal: Sapphire
• Tegimented: Fully
• Calibre: Ronda 715 Li
• Movement: Quartz oil filled
• Strap or bracelet: Strap
• Manufacturer's limited warranty: 3 years
• Warranty service: Sinn Germany

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WatchBuys Direct Price: $3,110.00
Availability:  In Stock - Ships Immediately


Condition:  This Sinn watch is brand new and unworn

Authorized:  WatchBuys is Sinn's official importer and distributor
This watch ships free to US, Canada, Puerto Rico, Guam and APO/FPO/DPO locations from NC with select shipping methods

Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap
Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap

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Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap
Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap
Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap
Sinn U50-T Hydro S Black Fully Tegimented on Double Textile Strap
Product Details

Oil Filled Diver's Watch for All Wrist Sizes

After seeing the immense success of Sinn's midsize (41 mm) U50 Collection over the past few years, Sinn fans probably could have guessed that this new watch would someday join the expanding U50 lineup. 

Sinn developed their first watch to feature an oil filled case in 1996, and that watch was named the Sinn 403 Hydro.  Now, 28 years later, the new Sinn U50 Hydro once again packages this technology in a 41 mm case size.  This version features a black, fully Tegimented (hardened) case and bracelet and is named the Sinn U50-T Hydro S Black.

Sinn 403 Hydro









Original Sinn 403 Hydro From 1996



The new Sinn U50-T Hydro S Black checks in at 41 mm, 3 mm less than the Sinn UX (its older brother) while maintaining a remarkable 5,000 meters of water resistance. 

This case design also provides a 32% reduction in total weight compared to the Sinn UX, and at just 11.8 mm tall, Sinn has managed to reduce the height by more than 11% compared to the Sinn UX.



While the Sinn U50-T Hydro S Black is closely related to the Sinn UX with its oil filled case technology, the watch actually shares much of its design DNA with the Sinn T50 series.  The hour markers, indices, and hands closely match those of the Sinn T50, but with red accents to capture the overall color scheme of the Sinn U Series.

In line with the other black Sinn U Series watches, the Sinn U50-T Hydro S Black case is made from Tegimented (hardened) German submarine steel by SUG in Glashutte, Germany.  Both the case and Tegimented bezel feature a DLC finish as well.

The oil filled Sinn U50-T Hydro S Black represents a unique and innovative approach to diving watches, offering exceptional legibility at any viewing angle, extreme water resistance, and durability for divers.



Built for Extremes

Unlike other Sinn dive watches, the Sinn U50-T Hydro S Black utilizes a temperature-compensated quartz movement instead of a mechanical one.  The oil filling creates resistance and friction that a mechanical movement would struggle to overcome.

Filling the watch with a clear oil greatly enhances the readability of the dial from any angle (including under water) and increases the water resistance of the watch.

The oil filling acts as a barrier against water intrusion despite immense pressure, making the watch incredibly water-resistant to depths of 5,000 meters. It is more than suitable for both professional and technical diving.



Reduced Internal Reflections

When it comes to reading the time on the Sinn U50-T Hydro S Black, you'll quickly notice that light behaves differently with this watch compared to standard watches.

With standard watches, as light enters a watch crystal, part of it passes through directly while some gets reflected at the interface between the crystal and the air inside the case. This reflection creates the dreaded "mirror" effect and reduces the clarity of the dial, especially underwater where light levels quickly diminish.

The Sinn U50-T Hydro S Black is filled with a clear oil with a refractive index very close to that of the sapphire crystal. This oil creates a more uniform medium for light to travel through. As a result, light entering the crystal experiences minimal refraction where the crystal meets the oil and travels almost directly to the dial, significantly reducing internal reflections and glare.

With less glare and distortion, the dial becomes much clearer and easier to read, even in low-light conditions like deep underwater environments. This is crucial for divers who need to make quick and accurate readings of their time and other critical information.



A Durable 41 mm Case


The watch case of the Sinn U50-T Hydro S Black is made from the same steel used in the construction of the outer hull of submarines.  The steel was procured by Sinn from a steel supplier to Emden GmbH, one of Germany's North Sea shipbuilding yards who construct submarines using the material.  

Another important and practical feature of the submarine steel case is corrosion resistance.  The case of the Sinn U50-T Hydro S Black resists the effects of exposure to salt water and salt water environments.

The black uni-directional rotating bezel is milled from the same submarine steel as the case and is Tegimented. The indices are machined directly into the bezel without the use of bezel inserts, which can corrode or come loose at deep depths. 



Important features of this watch include:

  • Oil filled case
  • Temperature compensated quartz movement
  • Black Fully Tegimented case made of German submarine steel
  • Black uni-directional Tegimented submarine steel bezel 
  • Water resistant to 5,000 meters
  • Screw down crown
  • Date display at 3
  • Functional reliability from -20°C to +60°C
  • Sapphire crystal with double AR coating
  • SuperLuminova on the hands and hours (glows green)

This watch is fitted with a Sinn double textile strap with black tang buckle.


Frequently purchased with this watch:

Watch specifications are provided by the respective watch manufacturer and/or other sources. Although we use best efforts to provide accurate information, we reserve the right to make corrections when advised of specification changes and/or content errors.


Sinn watches feature a number of cutting edge technologies, many of which are unique to Sinn. Please note that not all Sinn watches, including the watch on this page, use all of these Sinn technologies.

Among the more notable Sinn technologies are:


Tegimented Hardened Cases

Many Sinn watches are fitted with Tegimented cases produced in-house by Sinn's case making affiliated company in Glashutte, Germany.

Standard steel used by most watch companies has a hardness of between 200 and 240 HV (Hardness Vickers is a common scale used to measure material hardness). The Tegiment process produces a hardness of at least 1,200 Vickers which is five times harder than standard steel (and on some Sinn models up to nine times harder than standard steel).

The Tegiment process is not a coating consisting of a foreign material; instead the steel itself that has been hardened using a special engineering process that creates a hardened barrier. The base material is a type of stainless steel also used for surgical implants, and the stainless steel resistance to corrosion is further improved by the Tegiment hardening process.

The primary advantages to a Tegimented case are extreme resistance to scratches and other case abrasions, as well as increased resistance to corrosion.

Please note that certain Sinn watches are fully Tegimented (case, bezel) while others are Tegimented only on the bezel. Use the links below to view both categories.

  • View Sinn watches with fully Tegimented cases.

  • View Sinn watches with Tegimented bezels only.


Dehumidification Technology

A number of Sinn models feature cases filled with inert gas. Sinn has found that filling the case with inert gas can help prevent the introduction of moisture and humidity to the case, as well as provide a more stable environment for the oils that lubricate the movement.

The proper care of any mechanical watch movement mandates that these oils maintain both their viscosity and lubrication properties.

  • View Sinn watches with dehumidification technology.


Copper Sulphate Capsules

A number Sinn models use one or more copper sulphate capsules to absorb humidity trapped inside the case. Over time these capsules will gradually turn dark blue indicating that humidity has been absorbed.

The primary benefit to these copper sulphate capsules is a more dry and stable environment for both the movement and the lubricating oils. Together with Sinn's inert gas treatment these capsules form the basis of Sinn's Dry Hold Technology.

This technology not only provides a more stable environment for the movement, but also prevents fogging of the crystal when going from hot to cold environments or from humid to non-humid conditions (such air conditioned buildings).

  • View Sinn watches with copper sulphate capsules.


Extreme Antimagnetic Protection

Magnetism can cause dramatic swings in the timekeeping of a mechanical watch movement. People are often exposed to magnetic fields without even being aware - frequent high altitude flying, metal detectors, audio and video equipment, medical equipment and computer equipment can all cause problems with magnetism.

Many Sinn watches offer extreme protection against magnetism up to 80,000 A/m. Sinn achieves these results using a number of different technologies, including special case and case back construction, soft iron components in the case and protective rings surrounding the movement.

  • View Sinn watches with extreme antimagnetic protection.


DIAPAL Oil Free Escapement

Sinn caused quite a stir when they first released their DIAPAL technology. Beginning in 1995, Sinn began work to create an oil free escapement. With any mechanical watch movement, the aging of oil, especially in the escapement can create long term problems for that movement. Additionally, as movement oil ages, required service intervals become more frequent.

Sinn's early analysis to this problem provided a quick solution (at least in theory) - if you don't use oil, it can't age. The process began by exchanging the ruby escapements for diamonds (the word "DIAPAL" derives from the German name for diamond escapements) in order to achieve the desired effect. The designation stuck, even though today Sinn works with solutions taken from advanced nanotechnology rather than diamonds.

The result is a movement that proves so reliable that Sinn offers an unprecedented five year warranty on their DIAPAL watches.

  • View Sinn watches featuring the DIAPAL oil free escapement.


Hydro Oil Filled Technology

Sinn has developed a technology termed "Hydro" in which the entire watch case is filled with oil. Watches using this technology are based on quartz rather than mechanical movements.

By using this type of movement, Sinn is able to fill the watch with oil, which has the joint affect of greatly enhancing the readability of the dial and time from any angle (including under water), and increasing the water resistance of the watch even at great depths.

  • View Sinn watches with Hydro Oil Filled technology.


Submarine Steel

Sinn has created a line of watches featuring cases made from German submarine steel (the U Series). The steel was procured by Sinn from a steel supplier to Emden GmbH, one of Germany's North Sea shipbuilding yards who construct submarines from the very same steel.

Because of the special steel used from the submarine steelmanufacturer, the case resists the effects of exposure to salt waterand salt water environments.

These cases are produced in-house by Sinn's case making affiliated company in Glashutte, Germany.

This special steel is also amagnetic which means that is does not have magnetic properties and cannot itself become magnetized. The watch movement itself is protected from magnetic fields up to 4,800 A/m.

  • View Sinn watches built from German submarine steel.



EZM Mission Timers

Sinn is a partner for manufacturing watches for the German Special Forces, including SWAT, Customs, FBI, helicopter police, GSG9 and other units.

Beginning with the now highly collectible (and valuable) Sinn EZM 1, Sinn has grown this collection to some of the most durable and highly functional watches made and they remain among the most popular in the collection.

  • View Sinn watches in the EZM Series.




Service Notes for This Watch

This watch is powered by a quartz movement and the case is filled with oil.

Special proprietary machines and equipment are required to change the extended life battery and to refill the case with oil.

Because only Sinn in Frankfurt has the necessary machines and equipment to correctly service this watch, you will need to return the watch to Frankfurt approximately every seven years for service.