Sinn has always made no-nonsense tool watches that have appealed to the watch collecting community at large. In 2020, it followed in the footsteps of many other brands by taking its popular Sinn U1 dive watch and shoehorning it into a much smaller case. This smaller package is now called the U50 Diving Watch and is a great example of a brand following contemporary trends. As a former owner of several U1’s, I can confidently say that it’s a great watch that can be held back by its large size. Thus, the U50 to the rescue!!


The 41 x11 mm case construction of the U50 is the blockbuster feature of this new watch. The U50 retains the same overall aesthetic as its predecessor in every way other than size. What the user sacrifices for this accommodation is a 50% reduction in water resistance. You’ll need to restrain yourself and stay above 500m when skinny dipping in the Caribbean next season. If you can manage that, I think you’ll be well-pleased by the comfort afforded by the smaller case. The 11mm thinness should really stand out to those of you in the know — this is a 3-4mm reduction over the U1’s height. This is going to allow you to slip this watch under a shirt cuff, if so desired, but more importantly, it should keep the watch comfortable.

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Moving past the size of the watch, you’re left with a very utilitarian dive watch. Don’t mistake “utilitarian” for “plain,” however. The U50 is cased in matte submarine steel. This particular steel, for those not already familiar, is extra-resistant to saltwater corrosion — a nice feature of a purpose-built dive watch, if you ask me. The version Sinn sent me for review was one of its tegimented case watches. You can either get fully tegimented or a version that only has the bezel tegimented. For those of you new to Sinn’s technology, tegiment hardens the steel to a greater degree than you’d normally see, and the end result here is a watch case that will resist wear very well.

The bezel mirrors the case’s matte finishes. There are some well-executed scallops running along the exterior of the bezel, offering a nice grip when turning. This captive diving bezel has one of the best actions in the business, in my opinion, with solid clicks between each position and perfect alignment. Furthermore, the numbers and markers are etched into the surface of the bezel, then filled with paint. This should shield them from wear over the years, Lastly, the pip at noon looks a bit like a triangle with one peak lopped off. It’s large and should work very well in dim light to keep track of whatever you’re timing. It kept me from overcooking my burgers when I was grilling, for sure.

The last little detail to touch on is the 6mm crown at 4 o’clock. The texture Sinn chose is perfect for getting a solid grip. Offset crowns like this generally aren’t my favorite, but it does seem to work well for the design of the U50 and keeps the crown from digging into your wrist.

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Sinn opted for the Sellita SW300 in the U50. Sinn used to put ETA movements in its watches but switched a few years back. I’m not sure if this was for cost savings or due to the lack of availability, but here we are. I’m going to refrain from droning on here about the Sellita; these movements are known quantities at this point. Suffice it to say it’s a 25-jewel movement beating at 28,800BPH and boasting a ~42hr power reserve. These are good movements, and I wouldn’t think twice about it in the U50.


To talk about the U50, dial one must first consider the crystal. A flat sapphire crystal that’s been very effectively AR-coated on both sides gives the effect of there appearing to be no crystal at all. In my experience, double-AR coating like this looks great until it doesn’t. It is possible for the external AR coating to be damaged, and it’s tough to “not see it” once that happens. Just my two cents.

Moving on to the dial itself, you have a matte black dial with simple printing. Sinn is emblazoned in the upper center of the dial in its characteristic cursive script. Below, you’ll find U50, Automatik, and the depth rating of 500m in red. This is just enough text on the dial for me and, to my eye, appears balanced. Around the dial, there is a white printed minute track separated by printed indices. The white printing contrasts nicely with the black dial and paired with the AR coating on the crystal, this watch is exceedingly easy to read.

The last thing to touch on is the handset. I feel like the hands Sinn uses on the U1/U50 are pretty polarizing. But they do set these watches apart and, in my mind, they are the most obvious identifier. Like the printer markers, these are well-contrasted against the dial and will be very legible. It’ll be up to you if you like the aesthetic.


Sinn offers the U50 on either a steel bracelet (tegimented or otherwise) or a rubber strap. The example shipped to me came on a trimmable rubber strap. Once getting permission from the brand, I cut this strap down to my wrist size with little difficulty. Rubber straps that have curved ends like the Sinn strap does can be hit or miss, for me, but Sinn did really well. Trimming it allows you to dial in your wrist size perfectly; I’d just do it slowly. Once you’ve cut it, you can’t go back.

The clasp is massive. Edge-to-edge, it’s nearly 50mm, and chunky. I think it looks great and does a good job of balancing the watch on your wrist. If this were my purchase, I would opt for the tegimented version here, since this is going to be a high-wear area, but Sinn’s matte finish should hold up, regardless.

In the end, the thing to take away from this new offering from Sinn is that the brand is also adopting the trend of downsizing its catalog. The U1 is a popular tooly dive watch, but from what I’ve read in the forums, it seems like the size has been a barrier for folks to purchase one. The U50 should help make that decision for you. Size aside, what Sinn has done is create a very squared-away steel dive watch that has just enough uniqueness and flair to stand out in the sea of steel divers. The Sinn U50 is available as seen tegimented on rubber for $2,850 and on the tegimented steel bracelet for $2,920. There are a few configurations that the watch can be purchased in, so I just suggest you check out (if you’re in the U.S.). For more information on the U50, head on over to

Necessary Data
>Brand: Sinn
>Model: U50
>Price: $2,920
>Size: 41mm
>Would reviewer personally wear it: Yes, without a doubt.
>Friend we’d recommend it to first: Anyone who wants a purpose-built dive watch.
>Best characteristic of watch: The size.
>Worst characteristic of watch: Perhaps the handset, depending on your preference.


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