
Seiko Mod Urkasser
FAQs — Seiko Mod Cases
Which movements fit these cases?
All listed cases target **NH35/NH36** by default. Some skeleton/integrated builds may also accept **NH7x**—check each product’s fit notes.
What case sizes are available?
Common sizes include **37 mm** and **41 mm** for Royal Oak-style, **39–41 mm** for Aquanaut-style, **~40–42 mm** for Nautilus-style, and **42 mm** for SKX/5KX-inspired cases. See the product specs for exact dimensions and wrist presence.
Which dial size do I need (28.5 vs 30.8 mm)?
SKX/5KX and many **37 mm** builds use **28.5 mm** dials. Larger windows like **Royal Oak 41 mm** or **Aquanaut 39–41 mm** often use **30.8 mm**. Always match the case’s dial window spec.
Are crystals and bezels interchangeable between styles?
Usually **no**. Integrated-style cases (Royal Oak/Nautilus) use specific crystal heights/profiles and bezel geometries. Diver-style (SKX/5KX) cases support standard bezel/insert formats. Check each listing for compatible crystal profile and bezel type.
Integrated bracelet vs standard lugs—what’s the difference?
**Integrated** cases (Royal Oak/Nautilus) are designed for a matching bracelet and won’t accept standard spring-bar straps. **Standard lugs** (e.g., SKX/5KX, some Aquanaut) accept most 20/22 mm straps and bracelets—verify lug width in the specs.
Do crowns and stems come included?
Many cases ship with a matching **crown/tube**. Stems are cut to length for your movement during assembly. Review the listing to confirm crown type (screw-down/push-pull) and water-resistance notes.
Water resistance—what should I expect?
Ratings vary by case, crystal, gasket fit, and assembly quality. If you need swimming-safe builds, choose cases with stated WR ratings and assemble/test with proper gaskets and torque. DIY mods should always be **pressure-tested** if water use is intended.
Beginner tip: where do I start?
Pick the **style and size** first, confirm **dial size**, then select a **movement (NH35/NH36)**, **crystal** (flat/domed), and **bracelet/strap**. Our product fit notes will keep everything compatible.