Comparing two of Seiko’s entry-level enthusiast timepieces, the SKX007 and the new SSK001 GMT, makes for an exciting horological showdown as each of the two models have their obvious similarities, but striking differences as well. Today, we're delving into the legendary Seiko SKX and its contemporary counterpart, the Seiko SSK GMT.

At namokiMODS, we're all about celebrating watch tech and design and helping you make informed choices. Join us as we dissect the similarities and differences between these two iconic Seiko models that watch lovers have been raving so much about.


Evolution of the Legend: SKX007 and SSK GMT

Source: Reddit


The SKX007 has been a darling for Seiko fans for many years before its untimely discontinuation in 2019. All things must come to an end, as they say, even for great products with such a wide appeal. We can pronounce the SKX truly dead however, as the spiritual successor lives on in the Seiko 5 Sports line, evolving yet again in 2022 with the release of the SSK GMT trio.

The similarity of the case design is obvious at first glance, with drilled lugs and a mix of brushed and polished finishes on the curved body. The protruding crown guards make a comeback, and so does the love-it-or-hate-it Jubilee bracelet, though most reviewers say that the one on the SSK has a much-improved quality compared to the original.


Source: Watch Clicker


Taking a closer look at dimensions, both watches share the same width and lug-to-lug measurement of 42.5 x 46mm, showcasing their comfortable and versatile wearability and ensuring a balanced and stylish presence on the wrist. The lug widths are also identical at 22mm, tapering down to 18mm, catering to diverse strap options. Despite these similarities though, the water resistance rating for the SSK has been downgraded to 100m, half of what the SKX is capable of.

The first distinction you’ll probably notice is on the crystal, which while both use Hardlex material, the SSK adds a cyclops lens for a magnified view of the date window. The dials underneath of course feature different inscriptions, with the SKX boasting of its diver watch capabilities while the SSK emphasizes its GMT functionality. Both dials still use the same marker designs though – a mix of triangles and circles and oblongs – although the ones on the SSK sports polished outlines to add sophistication.


Source: Worn and Wound


The chapter ring on the SKX007 features index markers, a design choice that sometimes caused misalignments with the markers on the insert, a well-known flaw that owners can laugh about. The SSK001 also uses indices but with the addition of 24hr markers. Look outwards and you see that the elapsed time bezel insert from the SKX007 has been replaced with a 24 hour insert – all perfectly logical.

All lumed parts of the SSK001 are thankfully using the same bright and hypnotizing LumiBrite that also graced the SKX007.


Delving into the Movements

Source: Chronometer Check


The Seiko 7S movement has become a legend in the horological world, known for its reliability and robustness, and it has become doubly popular by powering the SKX007. Operating at 21,600 vibrations per hour (vph), the 7S movement offers a simple yet effective design with 21 jewels for added durability. This movement features automatic winding, powered by the natural movement of the wearer's wrist. While it lacks hand-winding and hacking capabilities, the 7S movement excels in longevity and requires minimal maintenance.

The heart beating within the Seiko SSK001 builds upon the foundation of the 7S. Seiko's 4R movement family features the same 21,600 vph, preserving the accuracy while providing smoother seconds-hand movement. A notable advancement is the introduction of hacking and hand-winding features for easier time-setting and reviving the movement if the power runs out, adding a layer of convenience to the user experience. Finally, the 4R34 adds the well-loved GMT complication while adding a measly 0.1mm to its overall thickness.


Modding Possibilities


There’s not one veteran Seiko modder who is not aware of the importance of the SKX007 in the birth of this hobby. Its modular design and immense popularity gave the perfect conditions for craftsmen, and later third-party manufacturers, to create compatible parts and alter the diver watch’s design. Now, you can build an “SKX007” from the ground up or mix and match thousands of part designs to create a completely unique watch.

The SSK001 (along with the SSK003 and SSK005) are all newcomers to the scene, available only for just a year as of this write-up. Despite all the similarities between designs mentioned in the earlier sections, not a lot of modding parts are cross-compatible between the two models. Slowly but surely though, mod parts suppliers have been releasing parts for the SSK line. If you visit our shop and search for “SSK,” you’ll see that we already have a dozen assortment of parts for you to customize your Seiko GMT, and the list is only getting longer.


Wrap Up

As you navigate the world of Seiko watches, remember that both the SKX007 and SSK GMT embody Seiko's dedication to crafting exceptional timepieces. Each watch offers its unique blend of style, functionality, and innovation. Whether you're drawn to the timeless charm of the SKX or the contemporary features of the SSK GMT, both watches uphold Seiko's legacy as a horological powerhouse.

And if you’re looking for crystals, bezels, or new GMT hands for your SSK, be sure to browse our collection so you can start making upgrades and customizations on your Seiko GMT, transforming it into the ideal multi-timezone watch for you.

Happy modding!

August 27, 2023 — Jeremiah A

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