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GS Watch Case - 39mm

Caseback (Fits Movement Types)

Important Note: In order for bracelet to be universally compatible with our oyster bracelet, final GS case will NOT have drilled through lug holes. The blue protector film on the crown is removable. Photos will be updated after the new year. Thank you.

ONLY 4 main components are needed to complete a watch.
Watch Case
Movement Holder (optional)
Tweezer (optional)


  • For the watch case, select your (1) Case, then (2) Bracelet (optional), and lastly (3) Caseback (To fit different types of movements).
  • For a complete watch, select your (4) Dial, (5) Hands and (6) Movement.
  • To have watch assembled, select (7) Assemble Watch. Please note that assembling the entire timepiece requires 2 to 5 business days prior to shipping.

Engineered by us and made exclusively for us with quality assurance by ISO 9001 Certified manufacturers.


The First and Exceedingly High Quality GS Case designed after Limited Edition Grand Seiko SLGH003!

Comes complete with double domed clear AR sapphire, caseback (solid or sapphire), screw down crown with optional solid brushed oyster bracelet.

Designed to fit all of our dials (28.5mm) and original NH movements (grey dial holding spacer). Additionally, case has ability to fit ETA2824/SW200/SW260 and ETA2893/SW330 movements. Special spacer and caseback provided.

The bracelet clasp is also designed to have micro-adjustment without the need for removing or adding links.

Watch case has a water resistant of 200m.

This watch case is 39mm.
For 36mm, visit here
    1. Quality Swiss Production Quality, ISO 9001 Certified
    2. Case Material 316L Stainless Steel
    3. Case Diameter 39mm
    4. Case Thickness 12.5mm
    5. Bracelet Width 20mm taper to 18mm
    6. Lug to Lug 46.5mm
    7. Lug Width 20mm
    8. Crown Screw down
    9. Crystal Double Domed Sapphire with Clear Anti-Reflective Coating
    10. Crystal Size 29.5mm x 1.5mm x 3mm
    11. Water Resistant 200m / 20atm
    12. Fit Movements NH35, NH36, NH38, ETA2824, ETA2893, SW200, SW260, SW330
    1. 1x Watch Case (Inclusive of sapphire and crown)
    2. 1x Oyster Bracelet (Depends on selection)
    3. 1x NH Sapphire Caseback (Depends on selection)
    4. 1x ETA2824/SW200/SW260 Movement Spacer (Depends on selection)
    5. 1x ETA2893/SW330 Movement Spacer (Depends on selection)
    6. 1x ETA2824/SW200/SW260 Sapphire Caseback (Depends on selection)
    7. 1x ETA2893/SW330 Sapphire Caseback (Depends on selection)

    All photos of watches with modification parts are for illustration purposes only and are not included with modification parts purchased.

  • Recommended Mods With:

    1. Swiss Super-LumiNova® BGW9 Hands
    1. A Complete Guide On How To Mod Your SEIKO Watch Dial And Hands (Includes Photos & Video)
    2. Learn about fitting dials with four dial legs

Customer Reviews

Based on 9 reviews
Mason W. (Longmont, US)
Using this mod part for: Custom Build w/ LA Dial
An Exceptional Case That's So Close to Perfection

Right off the bat, this case is a stunner. I don't have a lot of experience with aftermarket Seiko mod cases, but its easy to tell that the quality on this GS case is top notch, to the point that it could likely rival most of Seiko's Prospex offerings. The lack of sharp edges, the brushing consistency, the vertical brushing on the bezel, and very good delineation/variety between the brushed and polished surfaces all make this case appear far more expensive than it is. All of this combines to make it a far more interesting option than an all-polished or all-brushed Explorer case. The fact that it comes pre-fitted with a sapphire crystal is just icing on the cake and makes it a much more approachable (and affordable) option for people getting started with modding.

I was looking to build my own GADA (go anywhere, do anything) watch for my first ground-up build, and this case was perfect for that. For this build I chose to use the LA Bronze Medallion Diver dial and some milsub style hands from Rafflestime. The 39mm case fits very comfortably on my 6.75" wrist, and offers a great balance between formal and sporty. However, there are a few nitpicks that keep this case from being perfect and earning five stars from me.

The biggest thing that holds this case back is the lug holes, which other people have mentioned. I understand that the awkward lug hole placement was done to ensure universal compatibility with the oyster bracelet from the LA Explorer case, but I can't help but wish LA had stuck with the drilled through central lug holes from the early photos that were used during the pre-order. Ultimately I feel like LA should have made new end links specifically for this case, especially since the current end links don't appear to match the case lugs very well based on the pictures I've seen. This is why I decided not to get the LA oyster bracelet with the case, and I plan on getting a Strapcode Asteroid straight end bracelet instead. As for less significant nitpicks, the caseback threads felt rather rough, and personally I would have preferred if the vertical brushed section on the dial was a little wider to make it more prominent and better balance the visual weight of the brushed and polished sections of the bezel. Finally, the inside of the lugs also have some faint vertical lines that look like remnants from the machining/manufacturing process, which just feels out of place considering how refined the rest of the case is.

Ultimately, its a great case if you're a beginner, or if you just want something that isn't a diver or Explorer while retaining a degree of Seiko DNA. The nitpicks I mentioned are incredibly minor, and shouldn't stop anyone from using this case if they like the overall look. I have no doubt that LA will absolutely nail it if they ever do a v2 of this case.

Hey Mason! This is Adriel! I am super grateful and thankful for your constructive feedback. I definitely hear you!!! I will without a doubt touch base on every points mentioned. Undoubtedly, v2 will come like Explorer and I will ensure these points are sorted. Please do keep any more feedback/suggestions coming. I always do my best to push the envelop. =)
Thank you very much for this valuable review!! Adriel

Vincent B (Renton, US)

GS Watch Case - 39mm

Using this mod part for: Grand Seiko
GS case 39mm

The best quality watch case GS 39mm

Tom (Manchester, GB)
GS Watch Case - 39mm

As mentioned by another I do think the lug holes could be more centred so when using different straps the case and strap look more as one. Other than that the case is excellent and is now one of my favourite aftermarket case designs.

Everem Everem (Jakarta, ID)
GS watch case 39mm

Stunning case and hands
Thank you so much Adriel 😃🤙

Nicolas W (Vancouver, CA)
Using this mod part for: GS case and Shirakaba dial
Stunning Case, but not the bracelet.

The case looks stunning when I paired it with the Shirakaba dial. I opted for a leather strap rather than the bracelet. I wished it had drilled holes. The placement of the holes don’t quite aligned.

Greg Gubman (Claremont, US)
Case Gets 5 Stars. Bracelet Not So Much

Case is beautifully finished and looks awesome. Bracelet, however, did not work out. Lug holes are nearly impossible to align with the end links, and the end links protrude past the lug ends, which doesn't look great and extends the overall lug-to-lug length. I switched to a leather strap, and everything looks great. Also looks good on a jubilee bracelet with straight end-links.

HUGO GONZALEZ (Sacramento, US)
Using this mod part for: Skx007
Looks great BUT

Looks great but the lug holes are not even all around. The online pictures show drilled through lugs but not what I got. One of the lug holes looks way too close to the edge. I don’t know, everything else so far looks good. Haven’t put it together yet.

William Taft (DeLand, US)
Using this mod part for: SNKE63J1
GS Watch Case 39mm

I received the case today and I must say the pictures do not do it justice. It is perfect. The case is visually stunning and it feels like a very high quality piece. The oyster bracelet is weighty and very nice. Everything arrived very quickly and well packaged. I couldn't be happier. Very impressive product and service!

Watch expertly assembled by Ryan Bond at Right On Time Watches www.rightontimewatches.com