Sinn 104 St Sa I Review: The Ultimate White-Dial Tool Watch

Before I get into this review of the Sinn 104 St Sa I white-dial watch, I wanted to offer some of my thoughts and provide some context about the brand. Now, if you know me, you know I’m a longtime fan of Germany’s Sinn and its iconoclastic range of tool watches. all of which have that extra little bit of over-engineered oomph when compared to many of their rugged peers. Come to think of it, these watches actually have no peers, given their unique solutions to problems facing watches that actually experience adverse conditions.

Sinn History & Context

Founded in 1961 in Frankfurt by ex-military pilot Helmut Sinn, the brand's cultish popularity stems from its technical innovations, which include the so-called "Submarine" steel, developed for the modern German Navy and found in many Sinn dive watches. Submarine steel possesses a mechanical strength more than one and a half times that of normal steel, and additionally, it's highly resistant to magnetism, cracking, and corrosion. In fact, Sinn claims the alloy is completely resistant to prolonged exposure to salt water, something that few stainless-steel formulations can claim. Sinn also employs an additional technology for hardening both stainless steel and titanium surfaces under the Tegiment name. This treatment increases both hardness and scratch resistance even further, making for a practically bombproof finish. 

The caseback of the Sinn U15

Sinn also goes above and beyond when it comes to handling pressure. For its pilot’s watches, Sinn uses a case designed to handle the reduced air pressures found at high altitudes. If the external pressure outside the watch case drops, the difference in pressure inside and outside of the case can push a watch crystal from the inside out, so the case is designed to ensure that the glass doesn’t unexpectedly eject itself. Many Sinn watches are also gas-filled, which aids in keeping humidity out of the case. 

The Sinn UX

As for high pressure, Sinn’s UX line of dive watches incorporates an oil-filled case using the company's HYDRO technology, and because the oil acts to reduce external pressures at depth, these watches are resistant to a gobsmacking 5,000 meters. The oil also resists fogging, and makes the dial legible from almost any angle, an effect that resembles a high-resolution computer monitor, especially underwater. The UX lineup also employs an ETA quartz movement, because a mechanical movement would be unable to function within an oil-filled case. In addition to being reliable, the ETA 955.652 is temperature-stabilized, remaining operational from -4 to +140 degrees Fahrenheit. In short, you’ll likely expire long before these overbuilt watches do.

The Sinn 104

Some of Sinn’s most intriguing models are the ones that straddle multiple worlds in terms of purpose and capability. The Sinn 104 is one such watch. Ostensibly a pilot’s watch, the white-dialed 104 St Sa I W (Sinn’s official model name) plants its other foot in dive-watch territory, due to its upped water resistance of 200 meters and ratcheting bezel. But there are enough key differences that position the 104 as an aviation-centric model, albeit an incredibly hardy one. Grab your chute, and let’s jump into the overbuilt, Sturm-und- Drang-proof Sinn 104. 

Sinn 104 St Sa I Case

The 41mm case wears a bit smaller than its diameter might suggest, thanks largely to the sharply downturned lugs. When I say downturned,  we’re talking about a 45 degree angle — not an insignificant number, but the result is a beefy tool-watch case that’s surprisingly tailored, even for smaller wrists. In fact, it has a trim lug-to-lug of just 46.5mm, pretty tight for the case’s diameter. The finishing is almost exclusively polished, save for brushing on the reverse, and the circular brushed finish on the screw-down exhibition caseback. The semi-guarded crown also screws down, resulting in a dive-worthy 200 meters of water resistance. But since the 104 is technically a pilot’s watch, it’s also low pressure resistant, remaining unaffected by changes in altitude experienced during flight.

The bezel is another highlight, with a smooth 60-click ball-bearing action that needs to be felt to be appreciated. It’s also screw-mounted, yet another example of Sinn’s “nothing succeeds like excess” attitude toward build quality, and will shrug off hard knocks that might eject a lesser bezel from its case. The bezel is bidirectional, as befits a proper pilot’s watch, and the black aluminum insert is numbered to count down to a specific event, rather than measuring elapsed time as a standard dive bezel would.

That last point of distinction is a surprisingly useful one, as more people do things like time eggs, or need to know when to feed the parking meter, rather than actually fly planes. The sapphire crystal is gently domed, and offers antireflective coating on both sides, providing excellent legibility with a bit of vintage flair. The caseback also sports a sapphire window, offering a view of the movement within, and it’s a nice upgrade, even on a tool watch, for those who like to see how the horological sausage gets made, so to speak.

The optional bracelet features H-links affixed with hex screws, another  checkmark in the plus column for those who wistfully remember German engineering from that golden era of solid-feeling Autobahn rockets and their bank-vault builds. The finish alternates between the brushed H-links and polished centers, and features an improved, tool-free quick-adjust clasp. There’s also a five-link bracelet available, albeit on Sinn’s older clasp design sans the new micro-adjust. And if you’re not so enamored with the bracelet look, the 104 also happens to be a total strap beast, with just about any style of leather, fabric, or rubber strap looking fantastic on it. The 20mm lug width encourages wanton experimentation in this department, so swap away, friends. 

Sinn 104 St Sa I Dial

Think about the classic tool watches we all know. The Sub. The Speedmaster. The Navitimer. The Seamaster. Clearly the majority of iconic tool watches have black (or dark) dials, and to be sure, a broad swath of Sinn’s catalog follows this playbook. But this Sinn dial variant happens to be white, and it’s this distinction that’s part of its strength. Some of the best tool watches happen to have a white dial, like the white Seamaster Diver 300M, to say nothing of the Polar Explorer II, and they’re both icons in their own right. Make no mistake, this wintry compatriot can hang with either in terms of reliability and function-first aesthetics. 

In its frosty white guise, the 104’s dial is all business, with its information super-legible in a black-on-white design that looks every bit a piece of professional equipment. The lumed stick markers every 5 minutes are outlined in black, with the Sinn logo below 12, and the German spelling of “Automatik” above 6. “Made in Germany” flanks the marker at 6, and the double day and date windows at 3 are separately framed and outlined in black, a nice touch. And if you’re on a hot Duolingo streak, you can choose to have the day display in German. The lumed, black, syringe-style hands offer superb visibility and contrast, as does the pointer second hand. And apart from its black-on-white format, the dial maintains the look of a sober, no-nonsense instrument. It feels exactly like what it is: a serious piece of kit. 

Sinn 104 Movement

As far as the movement choice, Sinn goes with the reliable Swiss Sellita SW 220-1, a move that so many smaller and microbrands have made since the Swatch Group effectively killed off the ETA supply chain to outside watchmakers. The SW 220-1 is essentially an ETA 2836-2 clone, and the movements are interchangeable since they share the same dimensions. In other words, either one would drop right into the Sinn’s case. It’s a 26-jewel movement, with a rate of 28,800 vibrations per hour, or 4 Hertz, a power reserve of around 40 hours, and the SW 220-1 is shock-protected as well.

The movement offers magnetic resistance up to the DIN 8309 standard, with resistance rated at 4,800 A/m. And although the Sinn is most definitely a tool watch, it’s a nice-looking movement for the price, too, with striping, perlage, a gold-colored Sinn-branded rotor, and blued screws. Sinn specifies the top grade of the Sellita here, and anecdotally, the movements tend to run near chronometer specs as delivered.

Some Final Thoughts

To put a bow on things, I have a few thoughts, starting with what might be caveats for a few in the audience. On a purely superficial level, this is not a flashy timepiece, and it comes from a decidedly non-hype brand. In other words, if you’re looking to get noticed by anyone other than watch nerds, look elsewhere. This is not your watch. The fully polished case is a choice, normally a dress-watch one, but yet somehow, I think it works. One other thing to note: trying on a new Sinn in the U.S. can be tough, as the brand has only a single American distributor and no brick-and-mortar retail presence that I’m aware of. It’s a real shame, since the brand makes some great stuff, but you’ll have to rely on your fellow collectors in order to get handsy with these, perhaps at a local gathering like a RedBar meet.  

On the plus side, this thing is a badass, end of sentence. The build is utterly bombproof, and chock full of details that would likely go unnoticed by those not in the know, like its dive-watch level of water resistance, low pressure capability, the incredible ball-bearing action of the bidirectional bezel, and its unusual countdown scale that’s unexpectedly useful. The white dial, while less common than the mass-appealing black, is both striking in its look and a rare sighting in the wild. 

It maintains fantastic legibility, while standing apart from the crowd. And if you’re worried about a 41 mm case diameter being a bit extra, don’t be. The tidy dimensions and sharp rake of the 104’s lugs ensure a great fit for average-sized wrists. In conclusion, while the Sinn 104 may be couched as a pilot’s watch, given its many attributes, you might be surprised at its versatility, rendering it a superbly hard-wearing daily, no pilot’s wings required. The Sinn 104 St Sa I starts at $1,690 on a textile strap and $2,140 on the quick- adjust bracelet. I don't think I'm alone in my love of this watch, as it was also Teddy's most worn watch of 2024.