Owner’s Review: Four Years with the Sinn U50

The Sinn U50 felt like a revelation when it was released in 2020. Sure, it was based on the larger U1, a design that dates to 2005, but the U50 was the first to make this modern expression of Sinn design language approachable to a broader audience. As a result, the U50 falls into a rare sweet spot in size and design that you usually have to go back to the ‘90s to find. In an era when many of the great tool watch brands of yesterday are pushing upmarket with more luxurious offerings, a brand like Sinn stands defiantly committed to its core strengths. After four years of ownership, the appeal hasn’t waned. The U50 is more relevant than ever, and in my world, it remains the bar for dive watches under $3,000.

I’m usually quick to point out that we are spoiled for choice when it comes to premium dive watches these days; as a genre, it’s one that many start-up microbrands are drawn to for its broad market appeal. It’s also a space that’s been heavily watered down (no pun intended) as a result. I hear enthusiasts describe modern examples through the lens of great historical examples, as those seem to be common sources for inspiration for many new (and old) brands. Truly novel ideas expressed in the dive-watch space are few and far between, but there are some truly interesting examples out there. Chief among them, as you may have discerned by now, is the Sinn U50. 

The U50 isn’t a watch that feels like anything else. There is no old-school inspiration in its design, which is obviously also the case for the U1 upon which it is based. This is nothing new for Sinn, which has been doing its own thing in Germany for over 25 years with watches like this, and I’d point to the original EZM1 as setting the template for this line of thinking. There were no decisions taken for granted with that watch — from small choices, like the color of the date, to big ones, like the orientation of the crown and mounting of the chronograph at the central hand stack. This is the kind of thinking that led to the U1, and in turn, the U50.

There are other watches from recent history that had the potential to enjoy a similar route, but were instead repurposed to better suit the needs of brands with more premium aspirations. The IWC GST Aquatimer is a perfect example; the Zenith Rainbow Flyback, another. You could even make the case for the first-generation Omega Seamaster 300 fitting the bill here, as well. These are each special watches in their own right, and represent something sorely lacking from traditional Swiss brands these days, but that’s probably a story best saved for another day. 

The point is that the U50 still feels like a watch from the ‘90s in many ways. The case design and dimensions are neatly tidy, with no sign of bloat anywhere. There are no frivolous design choices, no polished chamfers, no ceramic inserts. It’s straightforward, and down to business, and boasts an impressive 500-meter depth rating in a remarkably small package. The case is made from seawater-resistant German submarine steel, hardened in Sinn’s hallmark “Tegiment” chemical process, which creates an additional protective layer. It can be difficult to parse the meaningful bits of all that; suffice it to say that the case of my own U50, which has seen its fair share of abuse, looks brand new. 

The Sinn U50 is best understood through its design and its dimensions, both of which work in harmony here. The design itself is easy enough to process in images, but the size and shape of the case truly must be worn to be fully appreciated. This is the only time I’ll make a comparison, but much like folks talk about the magic of Rolex’s Explorer II 16570, and how its case has a quality that’s difficult to express in numbers (all of which is true, by the way), I’ve found the same situation to be true here. The U50 is officially a 41mm watch, though that measurement is taken from the width of the bezel, which flares out ever so slightly from the case. In truth, and I can’t reasonably explain this, it wears like a 39mm watch, and that might have something to do with the relatively short lugs, which net to a 46mm lug-to-lug distance. The U50 is 11mm thick, with a nicely rounded transition to the caseback, so it nestles into the wrist with ease. 

In comparison to the also excellent Pelagos 39 from Tudor, the U50 feels smaller on the wrist. It is a millimeter thinner, but I suspect it has more to do with the smooth transitions of the Sinn compared to the very sharp edges on the Tudor. Additionally, if you take like-for-like measurements, the P39 is 40mm at the bezel, and if you add in the crown placement at 3 o’clock compared to the 4 o’clock placement on the Sinn, you’re left with a much closer all-around footprint than you might imagine. The U50 is a perfect example of why you shouldn’t put too much stock into the measurements of a watch on paper. 

Most importantly, the U50 wears incredibly well (and honestly, so does the Pelagos 39), and makes for an exceptional day-to-day option. The only thing holding it back in that regard is the design of the dial. That’s not to say it’s impractical, because it’s not, but it’s near brutalist in presentation, and won’t pair as gracefully with as many outfits as something like the P39, an Omega Seamaster, or the like. The hands are towering blocks that make for a highly legible dial, which is aided by the flat sapphire crystal that frankly disappears when viewed directly. Seriously, you’d swear it wasn’t there if you catch it in the right light (ironically, this is the achilles heel of another Sinn model, the EZM1, whose domed crystal is nearly impossible to peer through unhindered by glare). 

The design is unusual, but just enough to bring a truly unique personality to the table. It also pairs well with the distinctive bezel design. The bezel is captive, held in place by screws, and can be had in black (SDR) or in steel (standard). It is fully indexed, and the markings are done in relief, with infill of black and red to help them pop off of the surface. This bezel is unlike anything else out there, and it’s a design you really get pulled into the more you look at it. Four years later, and it's one of the many details about this watch that still brings a smile. 

Sinn has a slightly mysterious quality about it, at least around my neck of the woods in the U.S. Its watches are sold exclusively through a retailer called WatchBuys, which certainly hasn’t helped the brand’s ability to establish broad relationships with enthusiasts domestically, and the watches aren’t really marketed in any effective way. Their reputation comes almost entirely from the community and existing owners, and with a bit of research the lore goes surprisingly deep. The Sinn U50 is a watch that more people should be aware of, but it remains something of a niche product to the market at large. 

Sinn is a German brand with an enviable history, with no shortage of all-time great watches bearing its name. It has remained true to its original ethos, and as of yet, does not appear to be making moves upmarket by engineering more flash into its watches. The U50 is part of a lineage of great tool watches, which continues today with new models such as the T50, and it stands as a monument to the idea of “uncompromising functionality.” I handle watches in this genre for a living, and have seen more than I’d like to admit come through my collection over the years. Very few of them have made an impression like the U50, and if you ask me, it’s one of, if not the best dive watches to be released in the past 10 years.