Review: Siduna M3440 Professional Fly-Back Chronograph

Between 1971 and 1973, the Swedish Air Force, otherwise known as the Svenska Flygvapnet, issued a military chronograph produced by Lemania. About 400 units with the ordinance number M3440-051010 were issued to the pilots of the Saab J37 Viggen, an incredibly advanced fighter jet at the time. At the end of their service, most of these watches were returned, but a small number (an estimated 50 – 65 units) escaped retirement. As you can imagine, these “Viggen” chronographs are quite rare, and they’re beloved by military watch collectors worldwide. When they occasionally pop up at auction — and it’s quite unusual that they do — they don’t sit around for long. This history is part of the context for the watch that we’re looking at today — the Siduna M3440 Professional Fly-Back Chronograph.

Siduna, it should be noted, is not a new brand. Siduna came into existence at the end of 19th century in Bienne, Switzerland with a focus on pocket watches. In 1929, Siduna became Siduna Aktieselskab and was incorporated in Copenhagen, Denmark. The firm was primarily known for producing 18k gold chronographs with Landeron 51 movements before going the way of the dodo during the Quartz Crisis. In 2006, Stockholm-based watchmaker Folke Bertil Ingerlund purchased the trademark, and held it until his retirement in 2017.

Lemania “Viggen” via Bukowskis.

That’s where the story of today’s Siduna picks up. Francis Jacquerye, an industry veteran and former chief designer for Longines, took over the brand and decided that he, along with the help of Swedish watchmaker Peter Wadrbo, would bring Siduna back, continuing operation out of Sweden and shifting focus to iconic Scandinavian watches. And what’s more iconic than the “Viggen” chrono?

Editor’s note: the watch here is a prototype and features kinks that will be ironed out in the final production model. I’ll note any issues in the review below. 


Review: Siduna M3440 Professional Fly-Back Chronograph

Stainless steel
Caliber 13 Phi (Modified Valjoux 7750 with flyback functionality)
Galvanized black
CL/BL C3 Grade Super-LumiNova
Sapphire with A/R
Water Resistance
10 bar
42mm x 48mm
Lug Width

If the case here looks familiar, that’s intentional. Jacquerye reverse-engineered an iconic case produced by Ervin Piquerez — the same one used by brands like Breguet, Bucherer, Heuer, Rodania, Sinn, Wakmann, and yes, Lemania. Powering the Siduna M3440 is a modified Valjoux 7750, and in the case of the watch we’re looking at today it’s been additionally modified to have a flyback function. There’s also a version of this watch without this extra functionality.

The case measures 42mm wide and 48mm lug-to-lug, which, on this style of chronograph, is bit of a sweet spot. It has presence at 42mm, but it’s not overbearing given the busy dial and bezel, and the tempered lug length allows the watch to fit a multitude of wrist sizes.

The case measures 16.1mm thick, which certainly makes this one chunky, but it’s not out of the ordinary for a modern automatic chronograph (with a flyback complication no less), nor is it particularly strange with this sort of case. Some of Sinn’s similar chronographs feature cases just as thick. I’ve found that what really matters with these types of cases isn’t the numbers, but the way the watch is designed in profile, as well as the shape of the case back.

In profile, you can see that the mid-case is actually quite thin. On top of the mid-case (and partially sitting inside the mid-case), you have a polished bezel that overhangs and sits on a sort of extended platform. Both bezel and platform turn when you manipulate the bezel, which is quite easy to do because of the fine coin edge and aforementioned overhang. The mid-case is brushed and the bezel is polished, which creates a visual break in the case profile that keeps it from looking overly slabby. I love little design tricks like this, and it’s this extra effort that makes or breaks a design.

Mixed finishing from the bezel down to the mid-case.
Cross-hatching on the crown.
Prototype/sample case back.

Finishing here is pleasing mix of brushing and polishing, with prominent polished bevels along the edges of the lugs. The demarcation here could be a touch sharper, but overall it’s pretty good.

A set of pump pushers sit on the right side of the case flanking a large crown with cross-hatching on the end. The crown screws in and feels good doing so, and the pusher action is crisp with ample resistance. The bezel insert is satin PVD with luminous markers. The action is uni-directional and has a pleasing, springy click.

The dial is a relatively faithful recreation of the “Viggen.” We have two chronograph registers (30-minute counter at 3:00, running seconds at 9:00), a 12-hour scale rendered in Arabic numerals, and a smaller minutes/seconds track underneath. The dial is a very attractive deep black, which it gets from galvanic electro-plating. These are my favorite types of black dials. They’re somewhere between matte and glossy, and they have a certain crispness to them that makes them look great in any light.

The two recessed registers at 3:00 and 9:00 add some dimensionality to the dial, which I always welcome. They ever-so-slightly eat at the 2, 4, 8, and 10, but it’s so subtle that I’m not bothered by it. (The sub-dials on the Viggen cut the 3 and 9 in half, so I’m happy not to see that here.)

The handset is relatively straightforward: lume-filled swords for the hours/minutes, and simple sticks for the chronograph functions. The lume on the hands and dial is Super-LumiNova BL (Blue Line) C3 Grade, and it glows really well. The bezel, however, features Super-Luminova GL (Green Line) C3  at every five-minute interval, and it also has an excellent nighttime glow. One issue worth noting here on the prototype is that the luminous compound has bled out to some of the other markers on the bezel, which will not be an issue with the final production model.

Lume lovers will not be disappointed.

As I wrote above, the movement here is a modified Valjoux 7750 with a flyback function. Siduna calls it their Calibre 13 Phi, and it’s modified in La Chaux-de-Fonds. Most regular chronographs work as follows. You can start and stop the chronograph with a pusher (usually at 2:00), and you can reset with the second pusher (usually at 4:00). A flyback is different. It does everything a normal chronograph does, but you can also reset the chronograph without having to stop it first. So while the chronograph seconds hand is running, you can press the pusher at 4:00, and the hand will snap back to 0 and start running again without you having to actuate.

The watch comes on a padded, full-grain leather strap (black here, but there’s also a “rouille” option, which is a light tan, and “havana,” which is brown). The buckle is signed with Siduna. It’s a nice strap, but a bit too stiff for my liking. The problem with straps this rigid is that until they break in, they don’t sit on the wrist the way you want them to unless you cinch them on tight. So I swapped it out for one of our Model 2 Premium bands and I found it to be more comfortable and a better fit for the watch.

On a 7″ wrist with the OEM strap.
On one of our Model 2 Premium straps.

The standard chronograph version is €1,480 without VAT, and the flyback option is €1,880 without VAT, so that’s roughly $1,665 and $2,116, respectively. I think that’s fairly priced, especially for the flyback version, which you generally won’t encounter at this price point.

Overall, I think this is a really exciting offering from Siduna, As a fan of these sorts of watches, I’m happy to see a faithful recreation with some cool functionality at a reasonable price. These watches are currently available  with watches shipping the week after they’re ordered. Siduna

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Ilya is Worn & Wound's Managing Editor and Video Producer. He believes that when it comes to watches, quality, simplicity and functionality are king. This may very well explain his love for German and military-inspired watches. In addition to watches, Ilya brings an encyclopedic knowledge of leather, denim and all things related to menswear.