Seiko SUS GMT SCFF007 4S12



Many Seiko fans will be aware of the 4S15 SUS military watch that I have also mentioned before here and here.


This is another SUS, but a more useful SUS in my opinion because it comes with a non-independent GMT hand. In other words, you cannot adjust the hour hand independently of the minute hand but what you get is a non intrusive 24 hour hand that runs off the hour hand.

Interestingly at the time of release there were only 2 SUS mechanical models powered by the 4S15 and the 4S12 movements respectively. The 4S12 models (JPY 38,000) were also significantly more expensive than the 4S15 models (JPY 30,000), yet in the used watch market this is no longer the case.

I believe that this model was released around the same time, if not a little later than the popular 4s15 military models. This model came in three 3 color options, an aquamarine blue (SCFF009.  For some reason everyone on the Internet thinks that the model number is SCFF006, however the advertisement scan below confirms that the model number is SCFF009, NOT 006 ), flat black (SCFF005) and a stunning red (SCFF007). Pictures below from the internet.





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The three colors essentially contain the same 4s12 movement in the same case with bracelet. The red and blue dial variants are a stunning sunburst metallic finishing, however the black dial variant is simply a flat black. This is from my observation from photos available online and I have no idea why the black variant is a dull texture-less black compared to the more vibrant red and blues. One assumption I have is that the black variant was meant to be a more tone-down version of this model, while the blue and red dials are in their nature already more eye-catching, and hence would deserve the sunburst dial more.



These models lose the essential military watch design having absolutely no numerals on the dial, but retain the hidden date window at the 4 o’clock position.


Mlitary dial with full hour markings and hidden date window at 4 o’clock

Rather the GMT models traded the hour markings for 4 triangular markers at the compass points.

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Elongated metallic hour markers. Please note that the dial and GMT ring printing remain flawless. Any flaws perceived are due to scratches in the mineral crystal being reflected.

At the base of these elongated triangular markers we can see splotches of Lumibrite being applied. As you can see from my photo above, the application is uneven which is surprisingly to say the least. Perhaps in the late 90s, Seiko is not yet automated to the extent that it is today. I also need to clarify that the sample I have on-hand is unmolested since the day it left the factory so I can  attest that this is not the work of some amateur meddling with the watch.

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Minute markers. Any flaws perceived are due to scratches in the mineral crystal.

The minute markers and the seconds markers are white lines, with the minute markers being slightly more than twice as long. The 5th minute markers are the same length but twice as thick as the normal minute markers.

At first glance, this was actually a bit unsettling because the lengths do not appear proportional as compared to the usual watch dial designs. However I must say that the usage of the “elongated” triangular markers do match very well with the minute and second marker design.

The SUS GMT models also differ from the SUS military models in the design and utilisation of the chapter ring. In the SUS military, the chapter ring marks out the minute and second markings while in the SUS GMT it is a rotating 24 hr chapter ring. The bi-directional 24 hr ring is operated by the 2nd crown at the 4 o’clock position.

GMT function

dual time 1

One might wonder how the GMT function works in collaboration with the bidirectional GMT ring. The basic premise is that the owner will read off the 24 hr hand, which should be pointing at the 2nd time zone that the owner is interested in. The assumption made is that the owner will already know the time difference between his home time (shown by the normal 12 hr hour hand) and the 2nd time zone (shown by the 24 hr hour hand).  For example, I’m currently in Bangkok and I would like to track the time in Singapore (2nd time zone). The time difference between these 2 countries is 1 hr apart with Singapore being ahead. All I need to do is to rotate the GMT ring until the 12 o’clock marker is aligned to the figure ‘1’ on the GMT ring. From  that point on, I can easily read off the time in Singapore from the GMT ring.

dual time 2

Another common design of GMT watches is to have the names of the different cities printed on the GMT ring, which allows the owner to use the GMT function without having to know the time differences between countries beforehand. Such a watch is commonly known as a world timer, because this design would also allow the owner to know the exact time in each city around the world simply by reading off the hour that is aligned to each city printed on the ring, once he aligns his home city on the GMT ring to his current time.


Example of Seiko Navigator Timer 6117. Picture from antiquewatchbar

Alternatively, should the owner of the watch not have the need to travel across time zones, he can set the GMT ring’s ’24’ to be in line with the 12 o’clock marker. This way, the 4th hand simply acts as a day/night indicator. Many people may not know this, but in more expensive watches this is also how a day/night complication is added, simply by having a 4th hand that runs off the main hour hand at half the speed.

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The printing on the dial is a simple yet effective. The words “Seiko” and “Automatic” take pride of place at the top half of the dial, with no apparent bleeding in the printing. On the bottom half, we see the red “S” which represents this particular range “SUS- which stands for Simple and Strong”.  Other than the “S” printed in red, all other wordings are in white with no borders. Lastly, in line with other Seiko models, the movement number and the dial reference is printed on either side of the 6 o’clock marker.

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The date window is located at 4 o’clock and coherently presented on a black background with white words. The window is border-less, which is actually not so much a cost saving measure but to prevent distraction from the 4 elongated hour markers and 24 hr hand, leaving them to be the only reflective points on the dial. I very much prefer the design of the date window at either 4 o’clock because it stays “hidden” or at 6 o’clock because it looks more symmetrical.


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The hands remind me of the hands from my Kinetic Landmaster, all function without frills. The 12 hour, minute and seconds hands are painted a solid white to prevent any reflection and the middle of each hand is inlaid with Lumibrite for both the 12 hour and minute hands. The seconds hand has no lume.

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24 hr GMT hand

The 24 hr GMT hand works very well in keeping out of the way until the user needs to tell the time in the 2nd time zone. This is achieved by having a skeleton design, with only the tip of the hand leaving space for the application of lume.

The hand designs are shared with the SUS military, and  throughout the entire SUS range of watches, with some exceptions. Quoting from a famous post about the Seiko SUS “The hour hand is not only substantially shorter than the minute hand, it is also slightly wider, decreasing ambiguity, and furthering the ease of time reading. “

As to be expected with 4 hands, the crystal clearance is pretty high compared to normal 3 handers.

The only other GMT hand designs that remains truly hidden are watches with a 12 hr GMT hand (as opposed to a 24hr GMT hand), which can hide underneath the actual hour hand. However, I would not classify them as being a real GMT watch, because one will never know if its day or night in the 2nd time zone without doing some simple calculation. The very rare Seiko 5619 watches are one such example.


Seiko Duotime 5619. Picture from itauseikocollector blog

5619 movement specs

5619 movement specifications from Ranfft Watches


The watch is now about 20 years old and fortunately I do not detect any rotting of the lume in any of the hands nor markers.


Case and Crowns

This Seiko is my first watch with hooded lugs. “Hooded lugs” refers to watch designs where the lugs extend out from the watch head but cover the top of the watch band where we cannot see the attachment point between the watch and the band.  This is contrasted from “hidden lugs” where there are no lugs extending out from the watch head. The Seiko Tuna is a well-known example of a watch with “hidden lugs”.


Example of “hidden lugs” from the SBBN013. Note that the lugs do not extend out from the watch head at all.

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Example of “hooded lugs” from the SUS. Note that the lugs extend out slightly from the watch head.

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View from the top of a “hooded lug”. Note that we cannot see the attachment point between the watch band and the watch head.

As expected for a watch of this functionality, it comes with twin crowns, similar to the old compressor divers of the 60s. I really like the old twin crown designs because it does away with the external bezel, and dresses up the watch. Having twin crowns (assuming they are located at 2 and 4 o’clock positions) also add symmetry to the case, similar to chronographs.


Example of a vintage twin crown diver with internal rotating bezel. Picture from the internet.

The 2 crowns used are slightly different from one another in design. The crown at 3 o’clock is used for time setting, while the crown at 4 o’clock has a small dimple in the middle and used for rotating the GMT ring. Both crowns are non-screw down and unsigned.

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My first impression when i first got hold of this watch was that it was crafted out from a solid piece of steel due to its heft and girth. Certainly, it will not win any beauty contest compared to my Brightz titanium dress watches, but it showcases its own rugged functional beauty.

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The sides of the cases are slab-like and curves inwards gently at the lugs to hug the wrist. The sides are all polished with only a gentle horizontal brushing evident at the hooded lugs when you look at the watch face directly.

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Horizontal brushing evident across the hooded lugs

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Polished chamfer along the sides of the case

There is a polished chamfer along the edge of the case that adds some nice touches and break up the monotony of an otherwise functional but uninspired watch case.

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Difference between Chamfer and Bevel


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Turning the watch over brings us to the case back and there I found something very interesting. Observe the top part of the picture above and you will see many horizontal lines that form the curve of the lug.

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Illustration of how numerous lines can be used to form a curve

Those are obvious machining marks that were not smoothed out, unlike the cheapest Seiko 5 watches available today. The design looks intentional to me given that even the vintage Seiko watches do not have such obvious tooling marks.

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This model had a display case back with a world map on the glass. Before I took ownership of the watch, I had concerns that the image of the map could have worn off or be scratched off over time. Imagine my pleasant surprise on handling the watch, and I realised that this world map was actually on the underside of the crystal! This is a very clever design and also makes a lot of sense as having a printing on the outside of the crystal which is always in contact with a sweaty wrist or sharp metal bracelet is a sure way to lose the printing.


This is the only 4s movement with a 24 hr non-independent hand. There are several 4S movement variants with an independently adjustable 24 hr hand and this can be seen as a predecessor to those variants, offering almost the same functionality but at a fraction of the cost.

As far as I know this is also the last Seiko movement to feature a 24 hr non-independent hand, and probably also one of the cheapest and most reliable. That is of course assuming that you can even find one of these models.




SUS is the most popular and sought after defunct range of modern Seikos (1990s onwards) today. Certainly using the high end 4s movement only helps to establish it’s pedigree.

This is reflected in the extraordinarily high prices SUS military 4S15 pieces in the used market today can fetch, upwards of USD 500 for a simple stainless steel time only watch!

On the other hand, the somewhat more useful SUS GMT is priced lower despite wearing much better than the diminutive SUS military and having a much rarer 4S12 movement. To me, this represents excellent value for any Seiko collector, assuming you can still get your hands on one.

Good hunting.


One thought on “Seiko SUS GMT SCFF007 4S12

  1. Pingback: Seiko Alpinist 6R15 SARB013 | musingsofawatchaddict

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