It’s funny how we can reduce the history of a type of horology to a single event or brand. Just like we can quickly jump into summaries of complex historical periods or scientific discoveries so that we can get the gist of it. Too often watch reviews and articles glance over the details of things and simply sparkle a few key facts in the middle of large subjective paragraphs. I’m guilty of doing that as I don’t shy from sharing my opinions about watches and the industry in my encyclopedic articles, and so it never is too late to do the right thing and course-correct. Today we’re going to talk about a dive watch, and oftentimes reviews of divers include historical and design connections to one Rolex Submariner, Blancpain Fifty Fathoms, or Doxa SUB300. They were, after all, pioneers in the domain and dictated how a professional dive watch should look and function like. However, there are other models which have pioneered something else which we don’t often talk about and in their specific and appropriate context. 

You might have guessed it already: quartz-powered underwater exploration timekeeping devices and how this technology played a key role in democratizing a particular type of horology to the masses. Understand this: professional dive watches have existed since the 1950s and even before World War II, and quartz watches before the time the watch we’re about to dissect came to market. But what didn’t exist before were quartz-powered analog divers which were more reliable and more affordable than high-end mechanical ones designed and engineered in Switzerland. Besides Tom Selleck’s Thomas Magnum in the popular 1980s crime drama show, many professional and amateur divers relied on the original Chronosport Sea Quartz 30 first released in 1977. And today, Momentum, which was founded by the original creator of the Sea Quartz, keeps the legacy alive by having brought back this machine and developed it into numerous versions. Today we’re going to take a look at the most no-nonsense of them, the $329 USD Sea Quartz 30 Eclipse Solar. 

Specifications 

In the past two months or so I’ve reviewed many delicious battery-operated tool watches. And I’ve claimed in these reviews that micro and independent brands were at last embracing this type of horological technology because it makes sense—it’s cheap to acquire and replace, reliable and accurate. Granted, it doesn’t seem that most regular quartz or solar quartz calibers can actually be repaired but instead swapped, which isn’t ideal from an ecological standpoint. However one could argue the following: 1) buying a long-lasting quality quartz-powered timekeeping device is better than buying many cheap ones; and 2) solar-powered watches are said to last anywhere between 15 to 25 years without needing a human touch. This means the capacitor which stores the energy collected from light won’t need to be replaced for at least 15 years. In some instances, as they are related anecdotally in the world wide web, 40 years later the watch is still working and remains service-free. So on this fact alone spending $329 USD for a Momentum Sea Quartz 30 is excellent. 

Therefore, this Momentum is powered by a Seiko-made Epson VS43A caliber which comes with a standard accuracy of ± 20 seconds per month and a power reserve of 12 months* once fully charged. Moreover, quartz, and therefore solar-quartz calibers, are also known to have superlative resistance to shocks and magnetic fields to levels the highest of mechanical calibers cannot compete with, and that it takes between 6 to 120 hours to fully charge this little guy to get the 12-month run time. (How long it takes depends on the nature of the light source, its intensity, and the dial transparency rate.) All of these statistics and specifications make my horological heart flutter with great intensity as I love the idea of a watch that can keep on ticking for a year without needing anything from my lazy self and which will simply let me know when the battery is about to run out of juice by skipping a beat every two beats which gives me one day to recharge it. Because I won’t need to interact with the watch much, the screw-down crown measures a reasonable 5.8mm and is tucked away in-between large crown guards. 

*Momentum indicates 6 months but I went by the manufacturer’s spec sheet. 

The case of the Sea Quartz 30 Eclipse Solar by the way was proportioned with the 1970s in mind to keep its singular magic alive. So we find a diameter of 42mm, a lug-to-lug of 47mm, a thickness of 12.6mm and lug width of 20mm. At first, like many, I thought the case would be too large for my smaller wrist of 6.50”/16.5cm, but it isn’t and it actually looks the part for a 300m diver on account of a fine example of a Monnin case (read this review to learn more about it) where the paper dimensions are washed off by meaty lugs, wide polished chamfers, and a fully polished mid-case. On top of this gentle beast we find a flat piece of sapphire crystal with inner anti-reflective coating (which the brand doesn’t list on its website but which I assume exists on account of the high clarity of the glass,) below the case a polished case-back, and I believe a sapphire bezel insert but please don’t quote me on that. Moreover, the lume on the Sea Quartz 30 is outstanding as copious amounts of green-glowing and quick-charging SuperLuminova can be found on the hands, printed hour markers, and bezel markings for superlative nocturnal legibility. 

Again, all of this for $329 USD makes this Momentum a great deal and a steal. 

Design

Whenever brands decide to re-issue a watch they can go about its design in one of two ways: either by Xeroxing the original or by tweaking it to rejuvenate the design to make it better blend in with our contemporary horological epoch. Well, Momentum simply and smartly opted for the first option** which already endows the Sea Quartz 30 with a new-old-stock type of aesthetic which watch nerds would usually pay too much money for. And why bother reinventing a perfect wheel, should we ask? The dial therefore is as charming in 2025 as it was in 1977 when either Thomas Magnum or your dad went diving in Hawaii, as the plongeur-style handset—which allegedly first appeared in the middle of the 20th century—indeed gives out vintage dive watches vibes on account of its profoundly charming unbalance. A small white-painted baton-shaped hour hand visually clashes with a much larger orange-painted pencil-style minute hand which makes tracking the elapsed minutes on the count-up bezel as easy as it is to set-and-forget the Epson VS43A inside. The handset is complemented by a thin white-painted seconds hand though equipped with a large rectangular lumed element.

**I noticed tiny discrepancies in the shape of the hour markers on several photos on the brand’s website. 

Therefore all three hands pop from the black dial with great intensity, equalled by the massive printed hour markers which are made of such thick layers of luminescent compound that they always appear to be glowing akin to yesteryear’s supercharged radioactive markers. Each hour marker is further delineated by a thin white line so that they more easily detach themselves from the dial, so to speak, rendering them as easy to read as it is to see the bright sun floating against a clean blue summer sky. With large Arabic numerals plotted at the cardinal point save for the three—where we find the wide framed day/date aperture—reading the time is a quick operation as our eyes instantly calculate where the hour and minute hands are pointing even though the minute track is relatively discreet compared to the center portion of the dial. The former is nevertheless made of large printed minute hash marks, painted in the same hue as the brand’s logo and text which therefore take a backseat during dial-reading operations. Everything was therefore designed with a clear purpose in mind which worked in 1977 and still does today. 

The dial, however magnificent it is, doesn’t make up the full visual spectacle of the Sea Quartz 30 on its own as the Monnin-style case is quite spectacular in its very right. This style of case was first commercialized in the early 1970s by the way and Chronosport was one of the first brands to adopt it for its professional-grade divers. The Monnin case became, and still is, iconic because of the originality of its profile and because of how comfortable it is to wear despite its “larger” dimensions which constitutes one of its most glorious attributes. Indeed, it lays flat on the wrist akin to a F1 glued to the asphalt though it is wide and rounded and almost oval shaped, with, as we already know, wide lugs and equally wide polished chamfers decorating the latter, and fully polished case flanks which make the whole apparatus appear smaller and thinner than it actually is. In other words, the Monnin case makes an equal contribution to the vintage aesthetic as the dial does which I find to make for the perfect visual union. Don’t get me started on the bezel and its knurling, please don’t. 

The Heart of the Matter

The Momentum Sea Quartz 30 Eclipse Solar is a remarkable piece in a plethora of aspects which sells for a stupidly small amount of gold. Whether you’re looking at it from a technical standpoint—300 meters of water resistance, excellent lume, reliable movement—a value standpoint—as $329 USD is a small sum of money to depart with for a professional diver—a design point of view—as a timepiece which has retained the best of 1970s horological design flavors—or from a historical aspect—the first analog quartz diver in the world—this watch makes sense in today’s watch world as much as it did five decades ago. And whichever one of these four areas of goodness you would choose to justify your personal interest in this piece, you can’t go wrong with any of those as the Sea Quartz 30 (in all of its variants) is paws down one of the most singular, tough, reliable, and affordable professional-grade diver on the market today. What’s more, at last, is that it doesn’t have any distant look-a-like cousin which truly makes it special. 

So at the heart of the matter today is this: there was nothing like the Sea Quartz 30 in 1977 and there is still nothing like it in tumultuous 2025. Back then this gem of utilitarian horology retailed for around $200 USD which is the equivalent of $1,100 USD today adjusted for inflation which seems insane of a price to pay for it unless you are considering the fact that quartz calibers cost much more to produce and acquire barely a decade after that Seiko pioneered the technology. (To put this price in perspective, the ubiquitous Rolex Submariner retailed for the same price in 1977.) However expensive it was at the time of the OG, the Sea Quartz 30 was nevertheless an incredible tool which we now can acquire for a much more modest sum of money. So it is impressive and cool that Momentum decided to resuscitate and preserve this true icon of vintage diving equipment which today is at the reach of all of us. 

Conclusion

It seems that Momentum has released several versions of the Sea Quartz 30 in the past few years making small tweaks to the shape of the hour markers and day/date aperture which might be due to a change in production or in the choice of calibers. But overall the watch has retained 99.99% of its originality throughout the ages and it is a good thing. At the time of writing this review there are seven versions of this watch including one automatic one. The Sea Quartz 30 Eclipse Solar is my favorite one of all on account of the no-nonsense and brain-free nature of the solar caliber inside which pairs so superbly with the rest of its incredible specifications. I reviewed and photographed the version on the beads-of-rice bracelet which is the one that will set you back $329 USD. But you can opt for a black or orange rubber strap for $288 USD. Whichever version you go for, you really cannot go wrong with any of them. 

Thanks for reading.