SēL Instruments and their Bombproof Watches

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In a factory in the Arizona desert, Andrew McLean is building bombproof watches. 

We talk a lot about tool watches here on Worn & Wound. We review dive watches with impressive water resistance, and field watches with cases that are coated with materials to keep them scratch free forever. There’s no denying that there’s a market for purpose built, durable watches that stand up to the elements, whatever those may be, and lots of brands are currently filling that niche. 

What McLean is doing, however, appears to be on another level entirely. 

His company, SēL Instruments, was founded upon a desire to make an unbreakable watch. McLean’s background as a private contractor and consultant, work filled with travel to environments that were sometimes unforgiving, instilled in him an understanding that a watch is, above all, a tool. But it’s his experience as an EMT that really drives his desire to build watches that are unbreakable, over-engineered to a profound degree. 

“Imagine a scene high in the mountains,” he tells me,  “a high angle environment, tight quarters, multiple patients, deteriorating weather, a helicopter hovering directly over our team, various technical elements in place for both team and patient safety.  The last thing I want is to spend time worrying about my gear breaking.”

McLean, having experienced his share of cracked crystals and broken spring bars, set out to make something better. 

“For me, a watch was not a fashion accessory.” -Andrew McLean

The OmniDiver, their flagship watch, is a big, chunky tool watch that, even if you didn’t know about all the R&D that was poured into it, you wouldn’t have any trouble believing that it could stand up to massive depths and vicious  shocks. The 48mm titanium case is imposing, the incredibly unique bracelet (perhaps this watch’s killer app) looks, at first glance, like something you’d wrap around a tire to help it cut through snow. Some watches, maybe even most watches, are designed in something related to a tradition in jewelry. The OmniDiver is the rare watch that seems to be truly born of function first. With a starting price of $4,875, the OmniDiver isn’t inexpensive, but considering the amount of engineering that has gone into it, you can make a good case that it represents a compelling value.

“For me, a watch was not a fashion accessory,” says McLean, “it was a simple tool.  The four pillars of good watch design for me were always accuracy, readability, adaptability, and toughness.” 

The OmniDiver dial, up close.

Which isn’t to say that the OmniDiver doesn’t have a certain aesthetic appeal – it looks like an instrument through and through, and we know that there are plenty of watch lovers who crave that kind of simple, no frills design. But the watch, when viewed in the context of McLean’s philosophy, makes a lot of sense. 

McLean’s approach with SēL is service driven – he views his products as indispensable for a certain type of customer who either has a deep need for a truly durable watch, or otherwise just wants a lot of extra peace of mind. He also strives to avoid some of the customer service issues that watch lovers of all stripes have become increasingly familiar with. For example, SēL offers free battery changes on their quartz watches to encourage owners to send them back to HQ so a full pressure test can be completed. “I once had a jeweler change a battery for me in a dive watch and tell me only after it flooded that waterproofing was extra,” McLean told me, emphatically stating his astonishment. His goal is keep his customer satisfied.

Besides a strong focus on the customer, the other prevailing theme that runs through SēL as a brand is a devotion to R&D and rigorous testing of their products. “Lots of watches look like professional tools,” McLean told me, “the numbers often tell another story.  We’re pretty transparent about our testing and development. We intentionally break our own stuff all the time.”

Where the magic happens at SēL Instruments.

What does it take to break a SēL Instruments watch? A tool that the owner of the company proudly refers to as “Bombproof” without a hint of exaggeration of hyperbole? 

Well, quite a lot. 

Let’s take water resistance. Initially, the idea was for the OmniDiver to be water resistant to 11,000 meters (the depth of Challenger Deep, the deepest known point on earth’s seabed – because, of course). Beyond designing the seals that would keep the watch pressure resistant to such an insane depth, there are two other problems that come up with a task like this. First, making the watch in a size appropriate for daily wear, as opposed to a display piece that would have once been strapped to a submersible. And secondly: how do you test for this?

“We actually had to build our own 20,000psi hydrostatic test system,” McLean told me. Yes, yes you would have to do exactly that.

“We optimized the dynamic load paths that would be essential to stabilize the structure under those immense pressures so that the forces are directed to the strongest parts of the case and away from more sensitive areas,” McLean explained.  “In destructive testing, we took steel and titanium test cases to pressures that were actually distorting the case, but the bezels and crowns still functioned silk smooth after, and the seals did not fail.” 

The hydrostatic testing system used to test the OmniDiver.

So the team at SēL had to create their own test system to break one of their watches, but even the “broken” OmniDiver could still function at the bottom of the world’s deepest ocean. Ultimately, for production watches, McLean settled on a depth rating of 6,000 meters, which, he’ll remind you, is six times the depth of the world record saturation dive, so in many ways just as bonkers as 11,000 meters. But (there’s always a but), the OmniDiver can still make it to 11,000 meters if you really need it to, because SēL will, upon request, ship you a fluid filled Omni Diver, which dramatically increases its total pressure resistance.

The OmniDiver’s bracelet and clasp is another technical innovation that is really unlike anything on the market. The Wavlock Clasp features a full 24mm of micro-adjustment, and as opposed to a traditional tri-fold clasp where pressure is put on the hinges, the Wavlock is designed to absorb pressure in a titanium plate. The video below walks through the Wavlock’s functionality, and if you’re accustomed to a traditional clasp you may need to watch it twice to properly get your bearings, as it’s a radically different method of securing a watch to the wrist.

There’s obviously a ton of engineering wizardry happening behind the scenes at SēL, but it seems to all be in the service of providing an excellent, tailored experience to each customer. Digging through SēL’s Instagram page, I noticed an exchange with a prospective customer inquiring about the possibility of retrofitting a helium escape valve on an OmniDiver. Now, a helium escape valve on a dive watch is often thought to be unnecessary puffery, an extra feature that’s almost never actually used in a real world setting, but is thought to signal a certain amount of engineering know-how by the brand behind the watch. But because of this particular Instagram user’s handle, McLean had a hunch that this might be one of the few who could actually make use of the feature. 

“He is a hyperbaric welder and saturation diver working overseas,” McLean told me when I asked about the exchange. “We developed the OmniDiver Helium Pro because of his request and now offer it as an upgrade to the MKI OmniDiver on new watches. Existing OmniDivers can be retrofitted as well.”

The Wavlock clasp, at various stages of opening and closing.

Providing a custom helium escape valve (and then making that product part of the catalog) is perhaps an extreme example of doing right by the customer, but there are other ways this attitude manifests itself at SēL. McLean makes an effort to personally respond to every email within twelve hours, and they back up their products in a way that most watch brands simply can’t, or just don’t. The high accuracy quartz version of the OmniDiver, for example, has what is essentially a 10 year warranty (five years out of the gate, plus another five assuming an on time battery replacement and service at the factory). Between 2018 and 2019, not a single product was returned to SēL by a customer. 

If you take a look around the SēL Instruments website, it becomes clear very quickly that a big part of the company’s identity rests in being an American manufacturer. 

“Currently we are producing approximately 95% of our components in the Tucson, AZ workshop including cases, bezels, hands, crowns, bracelet/clasp components, dials, and many of our screws,” McLean told me.

The movements, of course, are Swiss, and SēL sees that as an obvious choice given their reliability. Interestingly, SēL sells the quartz and mechanical versions of the OmniDiver at the same price point, which isn’t really heard of in the watch industry, where a premium is typically expected for a mechanical movement. Here, it’s the quartz movement (an ETA PreciDrive) that’s the overachiever. It’s thermocompensated and shock resistant, and is accurate to 10 seconds per year. 

Between the innovative Wavlock clasp, the massive 6mm thick kyropoulos sapphire crystal, and the dive bezel that rides on silicon nitride balls for the smoothest possible movement without any discernible counter-rotation, the amount of research, technology, and pure problem solving that goes into each OmniDiver is truly impressive. So where does SēL go from here? Further expanding in-house production is priority number one, as it will allow the company to develop new products more quickly, and an increased flexibility in responding to customer needs. Also, robots. 

“We’re looking at adding robots to our CNC production line which would allow us to fully automate 3 shifts per day and bring costs down dramatically,” says McLean. “This type of investment can both increase margin for us, and reduce retail cost for the consumer.”

This really underlines SēL’s unique approach. While other watch brands, perhaps with a debt to history, focus on old-world handcraft and traditional watchmaking techniques as a way to lure customers to a world of luxury products, SēL embraces innovation at every turn, and celebrates doing things differently. “We never look for the easy way to do things – we look for the right way to do it,” says McLean.

With a catalog that includes not just the OmniDiver, but the recently introduced and slightly less intense OPTx watch, a blacked out diver that’s a little smaller than the OmniDiver but still rated to 2,000 meters, as well as a series of straps and multi-tools in their Bombproof line, Sēl Instruments seems to be carving out a niche as a brand that’s capable of fabricating just about anything you can imagine, as long as it’s incredibly tough. 

“We don’t fault anyone for thinking SēL watches are ‘over-built,’” says McLean, “for many, they totally are.  But for people who live and work in the harshest environments on earth, our level of engineering and quality can make a huge difference.”  


Images from this post:
Zach is a native of New Hampshire, and he has been interested in watches since the age of 13, when he walked into Macy’s and bought a gaudy, quartz, two-tone Citizen chronograph with his hard earned Bar Mitzvah money. It was lost in a move years ago, but he continues to hunt for a similar piece on eBay. Zach loves a wide variety of watches, but leans toward classic designs and proportions that have stood the test of time. He is currently obsessed with Grand Seiko.

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