The Topper Blog consists mainly of original writing by Rob & Russ Caplan with occasional special contributions and interviews. All photography in the blog is taken at Topper Fine Jewelers , or on location unless otherwise indicated in the photo captions.

Now at TOPPER: the Best-Kept Secrets of the PROSPEX Collection

One of the best parts about the Seiko Prospex ("Professional Specifications") line is the sheer range of diversity in design and capability maintained across a broad collection of watches – all of which are tailor-made for every budget and every adventure. Within the Prospex range, there have always remained the usual well-known legacy models, a few select fan-favorites that might be harder to obtain, and then there's another tier entirely – a series of truly hidden gems that, until now, haven't gotten the airplay at Topper that we felt they rightly deserved. With a few official summer weeks left on the calendar, we've received a very special allocation of some of the Prospex line's very best-kept secrets – including Japanese Domestic Market (JDM) exclusives built for both land and sea, all at prices that are fully exclusive to Topper Jewelers. For the full list of eligible watches, click here.

The Seiko 'Prospex' (Japanese shorthand for "Professional Specifications") story is a well-documented one, but in short, the term delineates watches in a collection which have been purpose-built with all of Seiko's best technologies, and to the specifications demanded by marine professionals, military pilots, and adventure-seekers alike, ensuring total dependability virtually anywhere on the planet. This includes extreme water resistance, enhanced shock and magnetic resistance, and improved legibility in any lighting environment – making any of these selections perfect for whatever adventure you have in store this season.

Seiko Prospex SBEX005 Marinemaster 1000m Hi-Beat Automatic Diver

There are simply no two ways about it: we're comfortable saying the dial of the SBEX005 remains one of the most remarkable Prospex dials ever made. Of course, the dial runs the risk of overshadowing the watch's impressively over-engineered 1000 meter-resistant titanium case, which houses the 8L55 Hi-Beat movement running at 36,000 beats per hour – 10 times per second, resulting in a silky-smooth seconds hand.

More notably though, like the SBEX001 reference that came first, the SBEX005 pays subtle homage to the first Hi-Beat Seiko diver 6159-7001 from 1965, but with a blue bezel and dial which houses a unique JDM-exclusive twist: a pure iron dial stamped with a classic Japanese textured "Seigaiha" motif, whose overlapping 'blue sea and waves' pattern has long been used in traditional art and textiles. This is a piece that truly needs to be seen to be believed, and like the classic watch fan adage – pictures will never fully do it justice. For more information, click here.

Seiko Prospex SBDB011 Marinemaster 600m Spring Drive GMT Diver

Though hardly a secret anymore, the SBDB011's rapidly dwindling supply makes it a natural entry to this list. Arguably the 'one Prospex to rule them all,' this unique Spring Drive GMT Diver is arguably the apex of over 50 years of Seiko's dive watch know-how. Crafted in a 46mm Dia Shield-coated titanium case, with an aggressive 'buzz-saw' rotating bezel and ingenious screw-locked bracelet, it's easily one of the most striking Prospex watches Seiko has ever offered. Inside, the SBDB0011 is powered by Seiko's 5R66 Spring Drive movement – a sophisticated GMT caliber produced at Grand Seiko's Shinshu Watch Studio, which is noteworthy for its independently adjustable hour hand, +/- 15 seconds-per-month accuracy, and generous three-day (72-hour) power reserve.

There are few watches that straddle such a fine line between traditional design codes, and ultra-modern capability, and the SBDB011 is absolutely one of them. For more information, click here.

Seiko Prospex SBDB017 200m Transocean Spring Drive GMT Diver

For a myriad of reasons, SBDB017 is the true unsung hero of the Prospex collection. Not only is it a markedly capable 200-meter diver, this detail-rich entry (just look at the depth and texture in the dial!) strikes an eminently wearable 44mm profile thanks to its light titanium construction, moderate thickness and short lugs attaching its integrated H-link bracelet (the latter of which yields some very compact lug-to-lug dimensions). Powered by the same 5R66 movement as its much larger cousin SBDB011, This Transocean GMT is also notable for being one of the most affordable entry points to date into Seiko's incredible Spring Drive technology, and a rare candidate for those looking for a comfortable dive watch with "true" GMT capability (an independently adjustable hour hand) and classically great looks to boot. For more information, click here.

This reference is also available in the more contemporary SBDB018 – a striking IP-coated black and rose gold variant with the same movement and capability, but with a completely different visual identity that reminds us a bit of samurai armor. For more information, click here.

Seiko Prospex SBEC003 200m Transocean Automatic Chronograph Diver

This JDM-exclusive Transocean is unique as it is the only mechanical chronograph in the Prospex catalog. In addition to its spectacular blue sunburst dial, SBEC003 is powered by Seiko's groundbreaking caliber 8R49, a column wheel automatic chronograph movement which also exhibits Seiko's innovative Magic Lever winding system. Like the Transocean GMT above, SBEC003's generous 46mm case proportions are nicely moderated by the integrated H-link bracelet design, which remains highly wearable even on smaller wrists. Unlike the GMT though, this Transocean is built with a stainless steel case – still beautifully finished from every angle though, and filled with details like a monobloc ceramic bezel, and DiaShield treatment to protect from everyday scratches. For more information, click here.

This Transocean reference is also available in multiple treatments: once again with the IP-coated black and rose gold treatment (ref. SBEC002) – a visual aesthetic that's further heightened here with the rose gold pushers and case band. It's also available with a classic black dial (ref. SBEC001), which should call to anyone looking for the classic Seiko Prospex dive watch aesthetic. For more information, click here.

Seiko Prospex SBBN027 Marinemaster 'Bumblebee' Tuna

There's an immensely cool Seiko Prospex video wherein Seiko engineers strap two Tuna watches to an underwater submersible unit, and drop it off the Continental Pacific Shelf, near the northeast coast of Japan. Without spoiling the full results, we'll just say that the 1000m Prospex Tuna far outperforms the already incredible depth rating on the dial. The Japan Domestic Market (JDM) exclusive SBBN027 shares the same remarkable capability as the tested instrument, thanks to the monocoque titanium case and custom-built 7C46 quartz movement (accurate to +/-5 seconds per month), but introduces in a few key details, including its polished ceramic bezel shroud, and brilliant yellow-orange bezel inlay, rightfully earning this reference the nickname "Bumblebee" by dive watch fans. For more information, click here.

Seiko Prospex SBED003 Marinemaster GPS Solar

The Seiko Prospex SBED003 Marinemaster GPS Solar is a true mariner's watch – designed to remain legible and survive harsh environments, while maintaining extreme, fully automated precision anywhere in the world. SBED003 is essentially a waterman's Astron, which you might recall is built with a titanium case around Seiko's proprietary GPS Solar 8X53 caliber, which displays a second time zone at 6:00 in 12-hour format, and then houses an AM/PM indicator at 2:00. This movement also houses a perpetual day and date calendar, which is corrected through to the year 2100. More importantly though, the 8X53 also synchronizes with GPS satellites to triangulate your current position – and can jump the hands to the correct local time at the push of a button. This is made possible, thanks to a GPS antenna ring, which is hidden beneath the two-piece black and white ceramic bezel, engraved with each of the GMT timezones. Measuring 48.5mm, the case itself wears comfortably, due to its titanium construction. Professional mariners will appreciate its 200 meters of water resistance, and the fact that this Prospex watch can be easily worn over the outside of a jacket or wetsuit, thanks to its ratcheting clasp. For more information, click here.

Seiko Prospex SBED007 Landmaster 'Great Traverse' GPS Solar

Like the SBED003 Marinemaster GPS Solar, the SBED007 Landmaster Kinetic GMT is a highly capable, multi-function adventure watch built around Seiko's GPS Solar 8X53 caliber – however this time, it has been subtly re-worked with alpinists and outdoor explorers in mind. Despite utilizing the same multi-timezone movement, SBED007 re-positions the chronograph pushers and crown to 12:00 – a move that resembles its predecessor, the Spring Drive GMT SBDB015 Landmaster. You'll notice this re-positions each subdial by 45 degrees, but the core functionality and feature set remain fully identical to SBED003. This includes the perpetual calendar, six month power reserve (on a full charge), and automatic GPS time zone synchronization thanks to the GPS ring tucked neatly underneath the green ceramic bezel, engraved with the city code for each of the 40 time zones the watch is capable of tracking. The proportions and water resistance of the DiaShield-coated titanium case also remain largely the same at 48mm and 200 meters (respectively), so choosing between the two should come down to simple color and pusher location preference. For more information, click here.

The Topper Blog consists mainly of original writing by Rob & Russ Caplan with occasional special contributions and interviews. All photography in the blog is taken at Topper Fine Jewelers , or on location unless otherwise indicated in the photo captions.