Sinn U50 S Mother-of-Pearl S Review

Sinn is a German watch brand with 60-year of history renowned for advanced technologies and tough, hard wearing tool watches.  The current owner and CEO Mr. Lothar Schmidt has been at the helm since 1994, after serving as a veteran technical leader at IWC.  Mr. Schmidt is a co-founder of SUG in Glashütte as well, a case maker who supplies to Sinn, Lange and other brands.  Sinn is an independent watch brand with a remarkable success story.  As a watch lover with engineering training, I knew that I would love to own a Sinn watch.

I almost bought a Sinn tide watch 240 St GZ at one point.  When I was growing up, I went to visit my grandparents in a seaside city every summer and went to swim in the sea.  We had to learn and calculate high tide and low tide based on a lunar calendar, so we would go to swim 1 hour ahead of the high tide.  That was why I was fascinated by the Sinn tide watch.  However, I don’t live near the sea any more and I swim in a swimming pool. That was why I didn’t pull the trigger on the tide watch, as I could not really put the tide function to use.   

When the Sinn U50 S Mother-of-Pearl S 500-piece limited edition was released earlier this year, I immediately knew that this was the watch for me.  The U50 is the smaller version of the 44mm U1, a highly regarded diver with water/pressure resistance up to 1000 meters.  The 41mm case diameter and 11.1mm case thickness make U50 a more suitable version for daily wear.  The specifications for U50 remain super impressive: high-strength and seawater-resistant German submarine steel, hardened surface coating, water-proof and pressure resistance to 500 meters and DNV certifications.  On top of all these, the individually numbered limited edition and one of a kind mother-of-pearl dial make it a collectable, rare piece.     

When the U50 arrived by delivery service on a Friday, it didn’t disappoint a bit! Just imagine the high expectations built up by the consistent rave reviews of Sinn tool watches over the years.  Furthermore, there were two major surprises for me.  The first surprise was the stunning beauty of this watch, once experienced in the metal. Could a tool watch this pretty and fashionable?  Watch enthusiasts often talk about the changing colors of watch dials under lighting conditions.  But there are no dials that could possibly top the beautiful light reflections from a natural mother-of-pearl.  I simply don’t get tired of looking at the mesmerizing dial.   

The entire watch is black, case, crown, hands, bracelet, everywhere except the mother-of-pearl.  I had never owned a black watch before and the beauty of this watch was beyond my expectation.  The bracelet is made of H-links, looking much like the bracelet on the iconic Patek Philippe Nautilus.  Sinn also provides rubber straps in a few colors and a number of leather straps.  

Another big surprise to me was the timing accuracy.  Inside U50’s sturdy case is Sellita SW300-1 movement.  I read that Sinn would regulate each movement to ensure that it is working in peak condition.  But my expectation was kind of low, based on my prior experience with 3rd party movements.  If you read my earlier reviews, you know that I would do timing tracking with a mobile app and measure the accuracy of every watch I own in daily use condition.  Now, here is the result for Sinn U50 -- and drum roll please -- measured over 8 days, the average error per day is +1.7 seconds!   This result was obtained with the U50 on my left wrist during the day-time and in crown-up position during the night.  The smashing timing accuracy puts U50 in the same league of watches costing 5 to 10 times more.  What a remarkable achievement by Sinn!

Last but not least, the watch wears very comfortably on the wrist.  Despite its slim size, the watch feels heavy, thanks to the dense German submarine steel.  I like the weight which ensures sturdy construction of this solid tool watch.  I took it for swimming a few times and used the bezel to time the length of my workout.  It has been my daily watch so far, including in the water. 

I’m extremely pleased with this Sinn U50 MOP limited edition and I don’t have any complaints so far honestly, which might not be a surprise to many die-hard Sinn fans.  While Tudor is often regarded as best values for the money among Swiss watch brands, I would say Sinn deserves this title for the German watch brands. Just think about that Sinn’s sister case maker SUG builds cases for Lange Odysseus, in addition to Sinn’s top models.   

This first Sinn watch for me really ticks all the boxes, technical spec, great look, accurate timing, unique MOP dial, and rarity.  A watch collector friend came up with a very nice name after seeing my pictures, “Black Pearl”.  Indeed, the two “S” in the model number represent black (“schwarz” in Germany), for both the case and the MOP.  It is quite rare to have such a beautiful “Black Pearl” that is at the same time a professional diver ready for all nautical challenges.