Seiko watches are among the best in the market, and people love their quality and affordability. Many watch enthusiasts also love modded Seiko watches. For a long time, modded Seiko GMT mods were out of reach, as there was no affordable Seiko GMT movement. 

This year – that has all changed with the Seiko NH34!

With the launch of the 4R34/ NH34 mechanical GMT watch movement, Seiko has opened the door to a new era in GMT watch mods. 

The NH34 movement is quickly becoming a popular choice for watch modders, and now modders can work with a super-reliable Seiko GMT watch movement that won’t break the bank!


The Rise of The Seiko NH34 Custom Watches

Source: @bbmod_france on IG


The NH34 hasn’t been on the market for long, but it is already a favorite with Seiko Mod Watches. Seiko has always been known for its innovative watches, and now modders can tap into the versatility the NH34 offers.  

The GMT function is a complication that enables you to track two time zones simultaneously (or three if you use the right kind of bezel insert). It is a  useful tool for travelers and businesspeople who often need to juggle multiple time zones. 



For a long time Seiko watch mods were limited to basic 3-hand models, but now watch modders now can customize their watches with a GMT function. The NH34 is built on proven architecture, and should be just as accurate as the NH35/6. 

The main specifications of the NH34 movement are:

  • 24 jewels
  • 21,600 beats per hour
  • 41-hour power reserve
  • Independently adjustable GMT hand
  • Automatic winding thanks with a bidirectional rotor
  • Hacking and manual winding

The Versatility of The NH34 Movement

The Seiko NH34 is going to be big in 2023. While the Seiko SKX007 mod is still popular, the Seiko GMT mod is the next big thing in Seiko mods. 

In addition to being one of the most affordable automatic GMT movements ever made, this movement is accurate, and very reliable. Basically, it is a natural extension of the NH35 and NH36, which are rock-solid movements that last for years. 

Although most modding parts are currently made to fit NH35/6s, many of the existing modding parts will work with the NH34. In addition, we are working on a full line of NH34 specific parts, so you can mod the watch of your dreams! 


Source: Seiko Watches


The NH34 is 0.4 mm taller than the NH35 because of the added GMT hand and the hand post to support it, so this may cause the second hand at the top to bump into the crystal. 

To solve this, you can switch to a double-domed crystal, as the extra clearance will give more room for the second hand. Not only that, but it’s also possible to replace the movement on an SSK watch and use parts that fit the case. 

However, as the new SSK models do not accept standard SKX007 casebacks, you will need our slim casebacks. Also, don’t forget to keep your OEM caseback gasket as some aftermarket ones are not always compatible.


The NH34 is Already Making Waves!

Seiko modders didn’t wait to start building amazing modded watches with the NH34. Here are a few watches that show how versatile the NH34 is, and the results modders are already getting with the new movement. 

Rolex GMT-Master II Homage

The “Batman” mod, which is how it is more popularly known in the Seiko modding world, has been a staple mod being built by watch modders for a while now. The signature black and blue bezel insert, mirroring the costume of the Dark Knight, is unmistakable and is one of the easiest ways to do a Rolex homage.

With the arrival of the NH34 GMT movement, this build will now be more “complete”, as builds and homages to the GMT-Master II have previously been notoriously missing a crucial detail: a GMT function. 

Here is a Seiko mod paying homage to the Rolex Master II ‘Batman’ made by @bbmod_france

The SSK Models that Seiko Should Have Released

Seiko released the initial SSK line with a black variant, navy blue variant, and an orange variant. All were well and good - save for the last one, these are probably the safest colors to release a new watch line in that will have the best appeal to the most people.

But what about people who like red, or purple, or Tiffany blue? They’re out of luck this time, but they don’t have to wait months (or maybe years) until Seiko releases a new budget GMT watch in the color that they like. Seiko mods are to the rescue!

And for people who love a deep green color, this mod by @jp_wristshop will be right up your alley.

Can we call this a GMT Build?

Minimalism has been a long-running aesthetic style in the watch mod scene. It is the complete opposite of flashy, and yet it makes for quite the noticeable watch. And there’s varying degrees to how minimalist you can make a watch too - here’s one that pushes the limit.

@jack_hypoxia’s “Interbeing” mod is probably as far as you can get with a minimalist watch sporting a GMT function. With 0 markers at all on the dial, chapter ring or bezel insert, there is almost no information provided save for the date window at 6 o’clock. This is not a watch, no. This is a statement. 

This watch reminds me of this thought-provoking passage from The Time Keeper by Mitch Albom.

Some Ideas for Your Next Seiko NH34 Mod

The NH34 is compatible with many existing parts in the Seiko spare parts lineup, so you have a lot of options if you want to start modding with the NH34 in the new year. 

The NH34 is a perfect fit for anyone who wants to create a Rolex GMT Master II homage, but it could also be used for Omega GMT homages, which aren’t as well represented in the modding community. 

While many Seiko dials don’t have 24-hour markers, you can use a 24-hour bezel, or bezel insert to keep track of the extra timezone. 

Here are a few places to look for more ideas, if you are into the NH34 modding scene. There are sure to be loads of new parts for the NH34 coming, so keep your ideas coming! 


New GMT Modding Options are Here! 

The Seiko NH34 is a big deal, and we already make a lot of watch mod parts that would be perfect for a NH34 mod. In addition to parts that are perfect for a Rolex or Omega inspired mod, we also have unique watch parts, like a Kanji dual time bezel insert!

At namokiMODS, we have all the Watch spare parts you need, and a whole lot more. If you are just getting into Seiko watch mods, check out our watchmaking kits, and get started the right way. 

Happy modding!

Januar 04, 2023 — Jeremiah A



The difficulty in creating GMT mods is finding dials that accommodate the movement. Looking forward to more suppliers providing dials that fit the movements


I just as soon yall build a watch for me can you send me a price list for the batman mod.

John Desmond:

I would love to add a GMT function to my SKX007, but I don’t want to lose the day function. Is there any way to add the day wheel and canon pinion from a 7S26 to the NH34 movement?

Frank Bianchi:

Is it possible to build a seikonaut using the NH34 movement. If so send me a list of parts I will need. I have movement.



Do you have a list of available parts. I’d like to build two watches asap.

Michael F:


Hope you’re doing well! Do you have a list of all parts to build the “Batman” mod?

I would like to order but i a bit unsure of all of the correct parts.


Phillip Burls.:

Hi. My name is Phil. I have been looking at your website on Seiko Modified watches with interest.
I am looking to purchase a modified Seiko for myself soon.
Also I’m looking at purchasing the Seiko Alpinist as well.
What is your price for the Seiko watches that you have in stock.
Also what models do you have.
Thank you for your time.


Will you be getting any bezel inserts for seiko SSK ?
Thank you

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