Build a Royal Oak-inspired Seiko mod with curated cases, dials, hands, crystals, crowns, and straps. Most 37 mm builds use 28.5 mm dials, while 41 mm builds require 30.8 mm dials. Compatible primarily with NH35/NH36 movements; some builds support NH7x skeletons. Review crystal profile and stem length in product notes.
FAQs — Royal Oak-Style Seiko Mod Parts
37 mm vs 41 mm builds?+
37 mm uses 28.5 mm dials; 41 mm uses 30.8–31.8 mm dials. Both typically run NH35/NH36.
Which crystals pair best?+
Double-domed sapphire is common for clarity. Confirm the profile/height recommended for your case.
Bracelet compatibility?+
Use bracelets made for the specific RO-style case size and finish to ensure end-link alignment.
Guides & Inspiration
Se alleLet customers speak for us
Perfect Seikoak mod
Everything was perfect. Shipping was fast and the product is of very good quality. In my opinion this is a the best Royal Oak mod you'll find on internet
Ismail Abdelmalki
Seiko mod – Royal Oak 37mm Silver
love the watch
Absolutely love the watch, it look realy good and adjusting the band was really easy
lars de groot
Seiko Mod Royal Oak OEM Birch
Very Reliable
Awesome watch! Excellent piece from these guys. This is the 3rd piece and I have never been let down:
H.
Seiko mod - Nautilus Skeleton Silver
Wonderful watch
Really well made, very happy with the product.
Jay B
Seiko Mod - Royal Oak Skeleton 41mm Gun Metal Gray
Very highly quality RO homage case
Very highly quality RO homage case. 37mm is a perfect fit for smaller wrists.
Samuel
Royal Oak 37mm Seiko Mod Case Silver
Perfect Case, Amazing Brand
This is the perfect size for this style of case. The quality of the cases is top-notch, they feel and look excellent. Additionally, Mathias from Nomods is also very friendly and professional and helped me out with all my questions and customization requests.
Oz
Royal Oak 37mm Seiko Mod Case Silver
Perfect case
Perfect size, perfect size case with the bezel being the right size. It is not too thick or too narrow, it is just right
Oz
Royal Oak 37mm Seiko Mod Case Rose gold
Very nice
Very nice case and very good quality
Nice seller
David
Royal Oak 37mm Seiko Mod Case Silver
Unique and gorgeous watch case
I am creating a custom watch build for my brother who works at a gym. I wanted something equal parts sport and elegance and the Petrichor meets and exceeds my standards for both. Really solid build quality with exceptional finishing, and a comfortable micro-adjustable bracelet to boot. I will be buying from NoMods again.
Samuel
Petrichor Seiko Mod Case Silver
