Automatic - 38mm - Steel caseback

The 38mm Steel Caseback is a precision-machined replacement caseback for Seiko mod builds on NH35-based cases. If you want a clean, closed finish on the back of your mod — without a display window — this solid stainless steel caseback is exactly what you need. It screws in flush and gives the case a refined, tool-watch look from any angle. Whether you are finishing a new build or replacing a worn or damaged caseback on an existing mod, this part slots in without modification.

Specifications

• Diameter: 38 mm — fits compatible Seiko NH35 mod cases
• Material: 316L stainless steel, brushed finish
• Style: Solid / closed back — no exhibition window
• Compatible: Standard 38 mm NH35 mod cases with matching thread pitch

Why choose a solid caseback?

A closed steel caseback does more than cover the movement — it completes the aesthetic of a purpose-built sport or tool watch. The flat profile sits flush against the wrist and eliminates the slight protrusion a crystal caseback can introduce. If you are building a compact, everyday-carry mod where wrist comfort and a clean silhouette matter more than showing the rotor, a solid steel back is the correct call. It also offers better long-term sealing compared to a mineral or sapphire display caseback, which can develop micro-gaps over years of use.

Part of your MedoMods build

MedoMods sources and hand-selects components for Seiko mods built in Germany. This caseback is sold as a standalone upgrade or replacement part — it pairs naturally with any MedoMods NH35-based mod case. Before ordering, verify your case thread size and diameter against the spec above — case tolerances vary between manufacturers. Shipped quickly from Germany, no customs hassle for EU buyers. If you have a question about compatibility with your specific case, reach out before ordering.