I’ve been a fan of the Sinn EZM 10 watch since I debuted the product back in 2011 when it was first introduced by Sinn. Later in 2012, I got an opportunity to check out the Sinn EZM 10 “Testaf” watch hands-on, and today I am pleased to offer what is actually a rather long-term review of a watch with a ton of impressive talking points from one of my favorite contemporary mechanical watch makers.

As part of this review, I’ve worn the Sinn EZM 10 on both the pilot-style leather strap as well as the metal bracelet. That bracelet is special not only because of its design, but because, like the case, it is produced from Sinn’s “Tegimented” titanium. Tegimentation is a process done by Sinn to harden metal. Sinn first began with Tegimented steel. The idea was to make the metal harder and thus much more resistant to scratches. True enough, when you buy a luxury watch, one of the worst things that can happen is when that watch gets its “first scratch.” Tegimented steel and other hardening techniques make that less common.

I was really excited when Sinn debuted Tegimented titanium, because compared to steel, normally, titanium scratches so much more easily. While Tegimented titanium isn’t as hard as say ceramic or sapphire, it is a vast improvement over normally finished titanium and until now I haven’t seen any scratches form on the case or bracelet of the EZM 10. I can’t claim not to have babied it a bit, but I am really impressed by the process and its durability. Even touching the Tegimented titanium case and bracelet feels nice. Think of what a Teflon-coated pan surface feels like – Tegimented titanium is a lot like that.

I like to call Sinn timepieces “super watches” because, at their best, Sinn produces some of the most practically durable mechanical watches around. They focus on a lot more areas than just water and shock resistance. The concept of durability and longevity is almost an obsession and runs deep within the Sinn brand, especially in some watch models like the EZM 10 (and other EZM models). “EZM” actually stands for “Einsatzzeitmesser” which is “mission timer,” and represents Sinn’s more “professional” watches. That is true, but the problem with that title is that most all Sinn watches are “professional” in their focus on function over things like luxury or durability.

For that reason, Sinn – based in Frankfurt, Germany – makes some of the best tool watches around. Anyhow, let’s get back to this notion of durability and longevity. Things like the Tegimented titanium case and bracelet are just an example. You also have things in the watch like Sinn’s moisture absorption capsule (copper sulfate) – which is in the side of the case and can be replaced if “full” – that prevents fogging from moisture that gets in the case, the diamond coated pallet (escapement) in the movement, the sapphire crystal over the bezel, and even more little surprises that any owner of this watch will come to appreciate over time.

Knowing the long list of things that Sinn put into the EZM 10 to make it work well as a watch, simply gives me a general sense of pride wearing this tool. A tool it is, and for those who love to appreciate well-made machines that perform the purpose they were designed to perform very well, will especially love a timepiece such as the EZM 10. To prove their point a bit more simply (well at least the notion was to be simple) Sinn wanted the EZM 10 to be, what I believe, is their first watch to comply with TESTAF certification standards.

TESTAF is a new technical standard for pilot watches that involves things such as functionality, legibility, and durability. So yes, even though the Sinn EZM 10 does a lot of things well, it is, at heart, a pilot watch. With that said, you could also argue it is a solid diving and land adventuring watch, too. The TESTAF logo is placed on the dial in black-on-black between the 7 and 8 o’clock hour markers. Legibility is truly excellent, even though there are so many hands on the dial and so much going on.

Part of what makes the EZM 10 so successful, is the utter lack of extra elements, no reflective surfaces, and an almost perfect sense of choosing the right materials for contrast and emphasis. Sinn uses orange for the chronograph hands and other elements such as the chronograph hours sub-dial, but otherwise everything is simple and monochromatic. It looks even more like a “tool watch” when you put on the titanium bracelet. The thick, padded leather strap is comfortable and of a very high quality but you don’t always want to wear the loud orange color of the strap. This is why I highly recommend also opting for the titanium bracelet, which is an additional purchase option.

Titanium really does help this rather large watch wear very comfortably thanks to weight savings. The Tegimented titanium bracelet is quite light, and while the case is not amazingly light, it would be much heavier in steel. With wide lugs and a thick 15.6mm case, the 44mm wide EZM 10 makes the most out of that size (“wearing large”) so the relatively light 95 grams (that is just the case) is super-wearable. Yes, the EZM 10 might be small for some wrists, but my medium-small wrist size can accommodate it just fine.

The case construction has a range of impressive elements, most of which you’ll never see. The EZM 10 is low and high pressure-resistant (200 meters of water resistance) and able to work in extremely hot or cold temperatures. Also, it is, of course, designed not to show wear easily. In addition to the Tegimented Titanium used for most of the case, the bi-directional rotating pilot-style bezel has a sapphire crystal over it. This means that markers under the crystal can be painted in luminant (which they are) and over them is a clear, very hard surface. Clicking the bezel in either direction is a watch lover’s pleasure…

You’ll also notice the flush chronograph pusher design. This is one of those more controversial elements to the design but I happen to like it. Everyone likes flush chronograph pushers but not everyone likes that Sinn decided to make them black in color. I am not 100% why they did this, but my presumption is that it’s to help remind the wearer that they are there. This might sound silly, but I think good tool design implies that no operating buttons or other controls are hidden from sight, even if you use them all the time.

The sapphire crystal over the dial is slightly domed and utterly lacks any reflection from light. Here we once again see something that Sinn is well-known for – applying many layers of anti-reflective coating on both sides of the crystal in order to make the crystal more-or-less visually disappear when looking at the watch face. Sinn does crystals like they should be done, and once you understand how a sapphire crystal has been properly designed and produced for a watch dial you’ll always see flaws in other watches that don’t take this element as seriously as Sinn does.

There are so many interesting things about the EZM 10’s case and dial that if it had a simple stock Swiss ETA mechanical movement, I would have been more than happy. Even though Sinn always regulates movements on their own, the Sinn EZM 10 would have been fine with just a Valjoux 7750, as some other Sinn chronograph watches come equipped with. Instead, the story of the movement makes the Sinn EZM 10 tale all that much more interesting.

My understanding is that EZM 10’s caliber Sinn SZ-01 movement begins with a 7750, but involves a lot of modification. In fact, I believe that the SZ-01 is Sinn’s first foray into making their own movement, given the serious in-house modifications. It will not be until sometime in 2016 that Sinn is finally able to introduce their first “exclusive” movement in the Sinn 6200 Meisterbund I watch.

The SZ-01 has a number of interesting elements to it. The first is how the dial is organized and laid out. Sinn decided to pay homage to the famed Lemania 5100 series of movements which had a central seconds and minutes chronograph with a 24-hour indicator. Likewise, the SZ-01 has a full 12-hour chronograph with a sub-dial for chronograph hours, and centrally-mounted hands for the chronograph hours and minutes. This makes reading the chronograph information a lot easier.

The other sub-dials on the EZM 10 are for the running seconds as a 24-hour AM/PM indicator. Some people don’t really see this feature has having a lot of use beyond when you are setting the time (as the watch does have a date feature), but I happen to find the AM/PM day/night indicator to be rather useful. It also helps people who need to calculate the current time in a 24, versus 12 hour, format.

The SZ-01 (SZ01) movement is, of course, an automatic, operating at 4Hz (28,800 bph) with about two days of power reserve. Another special feature exclusive to Sinn in the movement, is “DIAPAL” technology. “DIAPAL” stands for “Diamond Pallet” and is Sinn’s term for their oil-free escapement system. Unlike many other oil-free escapement systems which use silicon, DIAPAL is diamond-coated metal which allows for an extremely low friction environment. That means no oil is necessary in this crucial element of the movement – and that translates into more accuracy over time, as well as longer service intervals. So, years before even Rolex offered a five-year warranty, Sinn was offering five-year warranties on their watches with DIAPAL technology.

Putting the pieces together makes for one of the most impressive and highly-engineered Sinn watches ever. Even though the EZM 10 has technically been out for a while, Sinn still hasn’t upped the ante on what this watch has done from introducing Tegimented titanium, to the really incredible caliber SZ-10 automatic movement. Sinn even released the “baby brother” to the EZM 10 with the Sinn EZM 9 (hands-on here). What is the EZM 9? It has the same case and strap but with a simple three-hand movement.

Aside from being a tool watch lover’s dream, how does the Sinn EZM 10 hold its own from a fashion standpoint? Well, clearly not everyone in the world is going to be taken by all the little details like horology nerds are. Large, and inherently masculine, the EZM 10 has a classic look to it, which feels like a nice mixture between modern design elements and a look-and-feel that has been popular since the Omega Speedmaster became a hit.

Sinn, as a brand, refined the no-nonsense “function-first” watchmaking philosophy that all the best German watch makers are known for, in a way that lets tool watch lovers also wear a beautiful timepiece. With that said, no Sinn product will ever admit to being pretty, but we know better, don’t we? Mixing a series of sporty themes I think the EZM 10 is quite becoming. I wouldn’t call it a sexy watch, but it is very handsome at the least, and offers a welcome sense of harmony even though such elements of the design are more subtle.

I don’t think Sinn watches need to be “pushed” or sold to anyone, but rather, I think that the right people become attracted to the Sinn watch concept after being exposed to the brand. The no-nonsense personality of the brand even extends to their pricing and marketing. Pricing is still pretty fair and their marketing is mostly unheard of (at least to me). Sinn acts like a tool maker and not like a lifestyle brand – which is something that is mostly very good. It might make the brand a bit less accessible than other companies that are excited to sell anything to anyone, but the experience learning about and selecting a Sinn watch tends to be quite worth it.

For what you are getting, the price of the Sinn EZM 10 is very good, but it is clearly at the higher-end of what most people are accustomed to spending on a Sinn product. That means traditional Sinn buyers will need to save up a bit more, but at the same time, with all its cool features, I think the EZM 10 has the ability to even bring new people into the brand. Sinn sells the EZM 10 on the leather strap and additional straps as well as the bracelet are extra. I think this is a really stellar timepiece that doesn’t disappoint for what it is, and is something people could easily wear on a daily basis for years and be happy. Price varies from region-to-region but in the US, through WatchBuys.com, the Sinn EZM 10 is $5,290, while the Tegimented titanium bracelet is an additional $560. sinn.de

Necessary Data
>Brand: Sinn
>Model: EZM 10 TESTAF
>Price: $5,290 USD on leather strap. Matching bracelet is $560 USD extra.
>Size: 44mm wide
>Would reviewer personally wear it: Yes
>Friend we’d recommend it to first: Tool watch lover looking for the ultimate jack-of-all-trades mechanical chronograph.
>Best characteristic of watch: Wonderful assortment of features and details which make for value, durability, legibility, and longevity.
>Worst characteristic of watch: Might be sized too large for some wrists. Not everyone loves the look of the orange and black strap. Bracelet must be purchased separately as an option.