By Mike Compeau
“How’d they DO that?”
I have some trepidation as I begin writing this review. I’ve had the SeL Instrument OmniDiver Xos 42 for a number of weeks now, and writing a review of my experience with this watch had me constantly experiencing some aspect of wear, and then immediately musing, “How’d they DO that?” So, as you’ll see, I began to feel a bit like an apprentice engineer as I took on the challenge of reviewing this third generation tool from SeL Instrument.
And this is a good place to begin. SeL makes tools, and it’s apparent that their goal is to always make the best tool possible for its intended use. Optimum performance is their minimum standard. Naturally, these watches are not for everyone.
Some History
SeL Instrument began as an idea in Andrew McLean’s head in 2013 and he created their first prototype high performance dive watch in 2017. Shipping of production OmniDiver MK1 devices began in 2018. But, mind you, this is not your ordinary microbrand – SeL makes every single metal component in house, with the exception of their Swiss movements. Yes, even the screws. Everything.
That means they have purchased their own CNC milling machines for shaping their grade 5 titanium cases, as well as milling bezels and every component of their own designed Wavlock™ microadjustable titanium bracelets. In 2024, they acquired more high-speed CNC machines, as well as a 4-axis VMC milling machine, all to allow them to increase production 10-fold. And all in house.
Andrew and his team don’t mess around.
They call their approach “function first” and embody that ethos in optimizing for performance delivery in strength, comfort, precision, magnetic resistance, legibility, weight, water resistance, shock mitigation, accuracy and use-case functionality above all aesthetic considerations. It yields a watch that looks like nothing else on the market, and sets a high bar for USA-made manufacturing.
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Key Features of the SeL Instrument OmniDiver Xos
“We’re not in the business of easy.”
Andrew and his team set themselves up to create the pinnacle of ultra-performance for the new Xos OmniDiver. They optimized for three areas of performance: impact resistance, water resistance, and magnetic resistance. Choosing the engineering path to maximize specifications does bring new and difficult problems to solve. They don’t set out to do things the hard way, just the best way, and that’s not usually anywhere near ‘easy’.
Over the past year, I’ve followed some of those challenges: Setting up and configuring new milling machines to the desired (0.0001) tolerances, creating Labyrinth Flux™ – their own movement and dial suspension system to isolate the core goodies from external shocks and dampen impact inertia, refinement of their microadjustable WavLock™ bracelet that can be modified on wrist in seconds allowing 5mm increments and a built-in dive extension. No, this is not just a microbrand that sends drawings to a manufacturer overseas and waits to see if they arrive looking ‘good enough to sell’.
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Labyrinth Flux
The movement suspension system, what SeL refers to as Labyrinth Flux, relies on one principle component, also milled in-house. “It’s a single piece of compliant structure such that the inner ring (to which the dial/rehaut and movement are mounted securely) and this allows the center, heavy assembly of the movement/dial to float in three dimensions while the outermost ring is held rigid within the case walls. Much like a car suspension, it dampens impact forces so impacts are not fully transmitted directly from the outer case, and the movement is buffered from these environmental shocks. I had discussed with Andrew how his solution uses the same principle employed by Wyler in their Incaflex balance wheel — a shock resistant balance wheel design which similarly used a series of arms spiraling out from the center pivot to the outer weighted rim. Patented in the late 1920s, the Incaflex was the premier shock absorbency solution for watches until the introduction of the Incabloc floating jewel pivot about ten years later.
The labyrinth-like supports lend incredible resistance to shock, and the titanium component is so sensitive that in the image below you may be able to discern that the perfect circle is even slightly deformed by the modest pressure of the part between Andrew’s fingers. To his knowledge, no other modern watch is making use of anything like this shock and impact resistance feature.
Crowning achievement
The cross-hatched, ample crown, set at the well-protected 6-position between the lower lugs, is relatively easy to manipulate without removing the watch from the wrist, something we’ve all wished for at some point. The grip is unmatched, as the approximately 8.5mm diameter gives you plenty of purchase for making adjustments easily.
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My personal experience with the OmniDiver Xos
I’ll be blunt–I asked to review this watch from SeL. I have followed the firm on Instagram for over 5 years and been astounded time after time at the scientific approach to design taken by Andrew and the team, and by the unique solutions they create to typical watch problems. But I wanted to touch and wear a Sel OmniDiver myself. And they were gracious enough to accommodate me for a few very short weeks with the Xos.
So, I’ll admit, I entered into this review as a fan in the bleachers, watching from afar, and cheering on as I witnessed glowing reviews from big names like Hodinkee, Worn and Wound, and Ariel Adams. However, having the opportunity to wear this watch altered how I look at my other ‘tool watches’. I own a couple of watches I consider to be pretty robust ‘tools’ within the range of traditional horological definition. I’m speaking of the two watches you also see in the image below — A Citizen Fugu — a ProMaster automatic from the late 1980s, and an Omega X-33 — the titanium Speedmaster Professional model launched in 1998 as the official successor to the Moon Watch, and dubbed the Mars Watch aimed at use on the NASA space shuttle missions and on the International Space Station of the ESA.
The X-33 is also a titanium tool (the X-33 uses grade 2 Ti in the case), ostensibly designed with function and utility as the first consideration. However, it takes seconds for a user of the X-33 to note that the crown was designed entirely wrong for this watch design. A later generation of the X-33 addressed this, but I point this out to underscore this: SeL Instrument would never have released a crown designed to be pulled and pushed without perpendicular grip/grasp scoring. NASA and Omega? They took three years to fix this major oversight.
The Fugu? Every example I’ve seen of this watch, including the modern Eco-Drive versions of the past few years, frequently has noticeable bezel wobble when simply pressing down on the bezel at various points around the dial. We accept this because many of our Seikos and Breitlings and Omegas and, yes, Rolexes, often act the same; they all typically use a rather flimsy thin steel click spring and pent piano wire as the foundation of the indexing and rotation system We accept this ‘play’ in the assembly as ‘how they work’ or ‘not that noticeable’. The OmniDiver Xos? You’re unaware that the bezel is not fixed until you actually grasp its glove-friendly circumference, rotate it, and hear and feel the ball bearings and dual-piston indexing SNAP you into each of the 120 positions. No play. No wobble. It’s a distinctly different experience. Small wonder that this issue observed personally in so many other expensive dive watches was one of the original inspirations for Andrew to decide to start a company to make high-performance tool watches.
Every interaction with this watch serves to raise your expectations of other watches you own.
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So, when I say that “I believe the OmniDiver series is the work of the most obsessive and perfection-oriented engineers of tool watches in watchmaking today,” I think there’s a solid case to be made for that statement.
This prototype Xos, milled from the same grade 5 titanium stock used for the production watches, shrugs off any brushes with nature. I’ve left it out overnight in -5 degree cold, and retrieved it at sunrise, just sitting amidst the snow, happily counting down the seconds until its next adventure. In case you missed the dial text, this is a 2000m-rated diver. And the SeL Instrument design incorporates gaskets and lubricants that are better prepared for nature’s extremes than the Morton Thiokol solid rocket boosters for the Challenger shuttle.
Did I hike across Antarctica to McMurdo Station on Ross Island, or dive to find the Edmund Fitzgerald in the cold depths of Lake Superior? No. But this is definitely the watch anyone with those ambitions should be adding to their gear list.
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I grew to appreciate so much about this watch.
Lume: The in-house mixed lume acts like a veritable black hole for light, sucking down even the most modest ambient light to charge the special strontium aluminate mixture for what I have observed to be as long as 14-15 hours of glow. It’s extraordinary.
The hinged lugs: The special strap-adaptor lugs allow for and incredibly short lug-2-lug for a watch of this size. They conform perfectly to any size wrist and make wearing the watch on a 6.25” wrist or 8.5” wrist virtually identical.
Bezel overhang: a 1.25mm overhang of the bezel beyond the case makes grabbing the bezel AND moving the bezel a simple process. Additionally, it doesn’t matter where you grab the bezel, as you’ll find the same ease of grasping and turning possible along the entire circumference. That’s how all watches should work.
And the Crown: a grippy diamond-scored, highly tactile surface and an 8mm deep crown mean getting the time set, or the watch wound up to begin wear is very fast. And the crown is set at the 6-position, where as noted previously, it is most protected. It’s another of those function-first decisions that make the OmniDiver a joy to experience at every interaction.
Specs
| Case | Grade 5 Titanium (Ti-6AL-4V) US-produced Alloy 119g /w Isofrane strap 41.9mm Diameter 44.4mm Bezel Diameter 47.8mm Lug to Lug 14.4mm Thickness Unidirectional Bezel /w 120 Positions & 24 Ceramic & Teflon Ball Bearings (Dual Pistons) Screwed Caseback & Screw Down Crown 2000m Water Resistance |
| Dial & Crystal | Sapphire (shock isolated Kyropoulos) Matte Black Dial Recessed Markers Printed 24-Hour Index Custom Handset Super-LumiNova |
| Movement | Sellita SW200-1 Regulated In-House to COSC Standard -4/+6spd Labyrinth Flux™ (in-house movement & dial support system) 26 Jewels 28 800bph 38-Hour Power Reserve |
| Strap | Isofrane Strap or WavLock™ Bracelet |
SeL Instrument OmniDiver Xos
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What the OmniDiver Xos can’t do
Unfortunately, for the Richard Mille or Rolex crowd, this may never be a social flex watch. It may be noticed, but probably only when it’s glowing to light your way as you rise to depart a movie at the cinema, or when your camp-mate asks what you’re holding and using to drive in the tent stakes.
The OmniDiver is not jewelry. The OmniDiver is plenty happy to accompany you to your charity ball, or be your wrist companion at the board meeting, but don’t ask it to slide away unobtrusively–even at only 13.7mm tall. And, it’s far more likely to be mistaken for some accessory that you took off your jackhammer or acetylene torch when it’s seen off your wrist. That’s ok. No one is likely to try to slice it from your wrist on The Strand in London, either.
The obvious conclusion
This watch might not be for you. Plenty of enthusiasts find happiness in their Tissot PRX or Ball Engineer, or Omega Seamaster. The vast majority of Rolex submariners may never see moisture from the bathtub let alone 80-foot dives in Lake Michigan. For those who venture off the well-trodden path, the OmniDiver Xos offers plenty of distinctive performance (and brilliant lume) to make your hike or dive a complete and satisfying adventure, no matter where you’re headed.
The OmniDiver Xos is available at SeL Instrument starting at $4792 USD for quartz. The automatic configuration shown starts at $5204 USD. Numerous options allow customization of individual watches, to order. Me? I’m saving up.
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About the Author
Michael Compeau has made a career of education, organic analytical chemistry, new product development, and technology marketing. Somehow, over time, he acquired many, many watches, as well as the stories which bring them to life. You can follow him on Instagram.
Off The Cuff articles are full-length, hands-on reviews of the watch in question and represent the opinion of the author only. All photos are original, unless specified otherwise. If you would like to have your watch reviewed on this site, contact us here.
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