The First Seikonaut at 36mm — A Complete Integrated-Bracelet Case.
For those who like it small: the first-ever Seikonaut at 36mm. With its side notches it reaches 40.5mm, and 43mm including the crown — so a 36mm case wears with closer to a 40mm presence. Small, but a statement.
The sapphire crystal is coated with clear anti-reflective on both surfaces — double-sided AR — for an almost crystal-less view of your dial and hands. It comes as a complete case with an integrated bracelet designed specifically for it.
Everything but the dial, hands and movement is included. Tested to 200m.
A complete case — sapphire, crown, caseback and bracelet, all in.
Just add a dial, hands and movement. The integrated bracelet and double-sided AR sapphire are built in; there’s nothing to press or fit.
36mm that wears like 40.
Diameter 36mm — 40.5mm across the side notches, 43mm including the crown. A compact case with real wrist presence. Fits wrists from 13–20cm.
Double-sided AR sapphire.
Both surfaces of the flat sapphire carry clear anti-reflective coating (28 × 1.5mm), for a clarity that makes the crystal nearly disappear over your dial.
Integrated bracelet, built in.
A bracelet designed specifically for this case, with a 14.1mm integrated lug. Additional links can be supplied for larger wrists.
Complete and sealed.
Ships with sapphire, a screw-down crown, a clear sapphire screw-down caseback and the bracelet — all included. Rated to 200m.
Heads up — sold separately
Dial, hands & movement. The only parts chosen separately. Match the dial and hands to your NH movement (date / day-date / no-date).
Everything else — sapphire crystal, crown, caseback and integrated bracelet — is included. No chapter ring needed; dials seat on the grey dial holding spacer.
Dimensions
Materials & Finish
Compatibility
Water Resistance
The simplest build we make: the case is complete with crystal, crown, caseback and integrated bracelet. Add only a dial, hands and movement.
What's already in this purchase:
The complete watch case — flat double-sided AR sapphire, screw-down crown, clear sapphire screw-down caseback, and the integrated bracelet.
The 3 parts you'll need for a complete watch:
Optional finishing touches:
Want it built for you?
Tick the Assemble Watch option above and we’ll handle the full build in our Singapore workshop — case fitting, movement seating, crown alignment, caseback press and a function check.
Heads up: assembled watches require 2–5 business days of workshop time before shipping.
Once your parts arrive, see the How To Mod tab for assembly tutorials.
Only the dial, hands and movement are selected separately to complete your build.
All photos of watches with modification parts are for illustration purposes only and are not included with the case purchase.
Everything worth knowing before you build.
Customers praised this 36mm watch case for "outstanding quality" and "amazing build." The case wears larger (like 38-40mm), ideal for smaller wrists. The included bracelet is "comfortable" and "premium quality." Shoppers appreciated fast shipping and responsive customer support. One customer suggested adding bracelet half links for better fit adjustment.
This was my second seiko mod watch and it turned out perfect! I will definitely shop here again! :)
I've been wearing this Case daily for over a now and it still sits perfect and looks beautiful. I did lose one of the screws for the bracelet, but support replied within a day to send me a replacement, couldn't be happier!
Love this watch perfect size for a 7 inch wrist… wears like a 40mm this is my second watch From Lucius
After weeks of research for a quality case to make a nautilus tribute, I came back to the case proposed by Lucius Atelier, at first reluctant because quite expensive, it must be recognized that it has nothing to do with the low-coast cases ... and the bracelet provided is also of very good quality, comfortable and really well integrated, another world.
I absolutely do not regret my purchase, and encourage anyone wishing to assemble a nautilus to stop their research on this case
This is my perfect size watch size and in line with the current trend back to 36mm cases. The new dark blue dial offering made it a must buy with that perfect gradient outer edges and machined horizontal layers. Wore the watch today and non-people complimented it and a random stranger came up to ask if it was a 5711.
The bracelet tapers as it should and is of very good quality. Case is also similar and I'm loving the bezel to dial ratio much more on the 36mm
Adriel was extremely responsive and I really appreciate the hand written card I received with this watch, thank you for providing amazing mods and custom parts!
Amazing build quality, very satisfied with the product. Would definitely recommend.
Stunning case and bracelet, great quality. Amazing super-fast shipping and delivery is outstanding. It looks so classy. It looks better in person. I cannot thank Lucius enough, thank you for precutting the stem to fit my Seiko NH movement. This is my favorite watch mod from all my previous ones. Perfect size, the 36mm wears like a 40mm. Thank you. Jorge from CT, USA.
Great case and great service. Will be making future purchases.
Very professional, 6 day shipping to U.S..... thank you!
Words cannot do this watchcase justice. The quality is so high, I am so impressed once again with the products of Lucius Atelier. This watch has to be experienced in person to really see just how good it is!
This is such a well-built product. It looks and feels like a high-end luxury piece. I recommend getting the solid case back to shave an extra 0.6 mm off the profile for a perfect fit on the wrist.
Amazing case, looks phenomenal 👌
I felt that the case of the previous GS was not good, but this time it was improved!
I litterally found the perfect watch that I’ve been looking for after years. A nicely sized watch with the amazing Gérald Genta inspired look that suits my 16.5 cm wrist perfectly. The ability to choose every single element, from the dial to the hands, is a big plus. Furthermore, the watch was shipped extremely quickly after my order, and Adriel replies to e-mails very fast and is a very nice person. I am very satisfied with my purchase and will definitely order more in the future. Cheers from Switzerland !
The parts fit perfectly without issues and it looks gorgeous. The only improvements I'd like to see are the inclusion of bracelet half links and perhaps a lighter-coloured dial to match the true Tiffany blue.
Very happy with my build. I got inspired adored seeing a YouTube video (SVK Watches) and couldn’t help myself but to order one. Fast shipping and great quality products.
The availability of a smaller 36mm case was the reason I decided to put together a seikonaut build. Fits my wrist perfectly since the lug to lug wears bigger.
The case finishing and quality is great. Bracelet is comfortable.
Adriel also responded really quickly to a question that helped out a beginner modder like me.
I did end up using a different dial which was more muted that the Turquoise dial available.
The bracelet is comfortable and feels quite heavy and premium. Beautiful finish on the case and overall really good quality. It does wear a bit bigger than the 36mm might suggest, but i suppose thats in those Nautilus style cases‘ nature. Can recommend!
I was pleased to find this case set with an appropriate bracelet. It’s stated at 36mm but the case is actually more like 40mm, quite a difference, but still a better design than the last one. Check out my in depth video review here: Seiko-Naut Tiffany Blue 36mm-40mm! Lucius Atelier Nautilus Style Parts Review
https://youtu.be/cqKuT891zCI
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![Seikonaut Bracelet 20/16mm [TITANIUM] - - - - Lucius Atelier - Swiss Quality Seiko Watch Mod Parts](http://luciusatelier.com/cdn/shop/files/Seikonaut-Bracelet-2016mm-TITANIUM-Lucius-Atelier-Swiss-Quality-Seiko-Watch-Mod-Parts-7_2000x.jpg?v=1745004195)
