Essential Parts for Seiko Mods: Complete Guide (2026)
In This Article
Every Seiko mod is built from the same core parts. Understanding each component — what it does, what it costs, and how to ensure compatibility — is the foundation of successful modding. This guide breaks down the essential parts you need for any Seiko mod build.
Essential Parts Overview
| Part | Function | Price (Nomods) |
|---|---|---|
| Case | Housing + bracelet + crystal | $110–$195 |
| Movement | Automatic engine | $55–$95 |
| Dial | Watch face | $29–$40 |
| Hands | Time display | $28 |
| Crystal | Glass cover | Included with case |
| Chapter Ring | Index alignment ring | Included with case |
The Case
The case is the foundation — it determines the watch's size, style, dial compatibility, and overall aesthetic. Nomods cases include the bracelet, sapphire crystal, crown, chapter ring, and gaskets. Options include:
- Royal Oak 37mm ($149) — 28.5mm dials, octagonal design
- Royal Oak 41mm ($110) — 30.8mm dials, larger size
- Seikonaut 40mm ($149) — 30.8mm dials, Nautilus style
- Petrichor 37mm ($195) — 28.5mm dials, original design
The Movement
The movement is the watch's engine. All Nomods cases accept Seiko NH-family movements. Top choices:
- NH36 ($55) — budget, day-date
- NH35 ($85) — date, most popular
- NH38 ($85) — no date, clean look
- NH72 ($95) — skeleton, best for display casebacks
For a full movement comparison, see our complete modding guide.
The Dial
The dial defines personality. Two sizes exist: 28.5mm and 30.8mm. Your case determines which size you need. Options include waffle, sunburst, skeleton, and sector designs from $29-$40.
Tank-style Seiko mod — the Cartier-Tank rectangular build path.
Seiko Black Bay mod guide — the vintage-Tudor diver build path.
The Hands
Hands must match two things: (1) the movement stem size (all NH movements use the same) and (2) the color tone of your case and dial. Our hands come in Silver, Gold, and Rose Gold at $28.
The Crystal
All Nomods cases include a sapphire crystal with blue AR coating. Sapphire (Mohs 9) is far more scratch-resistant than mineral glass. See our Sapphire vs Hardlex guide.
Parts Cost Summary
A complete build with Nomods parts starts at $222 (Royal Oak 41mm + NH36 + dial + hands) and tops out around $358 (Petrichor 37mm + NH72 + skeleton dial + hands). See our build guide for full cost breakdowns.
Frequently Asked Questions
What parts do I need for a Seiko mod?
Four core parts: case, movement, dial, and hands. Nomods cases include the crystal, chapter ring, bracelet, crown, and gaskets.
How much do Seiko mod parts cost?
Cases: $110-$195. Movements: $55-$95. Dials: $29-$40. Hands: $28. Total build: $222-$358.
Are parts from different suppliers compatible?
Yes, as long as they follow the NH35 standard. Check dial size (28.5mm or 30.8mm) and movement type before ordering.
our Seiko mods page — the full Nomods catalog of prebuilt watches and parts.
Seiko Aquanaut mod guide — the Patek-Aquanaut sport-luxury build path.
Read More
- Build Your Own Custom Seiko Watch
- Modifying Seiko Watches: Complete Guide
- 28.5mm vs 30.8mm Seiko Dials
- Sapphire vs Hardlex Crystals
- Browse All Parts
Nomods is not affiliated with Seiko. All watches are independently built using Seiko-compatible movements and aftermarket components.
