Seikonaut 40mm Case – Rose Gold
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- Genuine 316L Steel & Sapphire
The Rose Gold Seikonaut wraps the ultra-thin Nautilus silhouette in 20-micron rose gold PVD plating over 316L stainless steel. At 9.95 mm with a solid caseback, this 40 mm case delivers a warm, luxurious tone while keeping the slim wrist presence that defines the Seikonaut line. The sapphire crystal is available with clear or blue AR coating, and the screw-down crown provides 50 m water resistance. Compatible with all standard NH-family movements and 30.8 mm dials, this case is built for modders who want rose gold warmth without the bulk of typical Nautilus alternatives.
Specifications
| Specification | Value |
|---|---|
| Diameter | 40 mm (10H–4H) × 38 mm (12H–6H) |
| Thickness | 9.95 mm (solid caseback) / 10.3 mm (exhibition caseback) |
| Material | 316L Stainless Steel with 20-micron rose gold PVD |
| Finish | Brushed and polished rose gold |
| Crystal | Sapphire (clear or blue AR coating) |
| Water Resistance | 50 m |
| Dial Fit | 30.8 mm |
| Crown | Screw-down, included |
Compatibility
Movements: NH35, NH36, NH38, NH70, NH71, NH72 — all standard Seiko NH-family automatics fit without modification. The crown stem must be cut to length during installation.
Dials: 30.8 mm dials only. Pair with rose gold or warm-toned dials for a cohesive look, or use a contrasting dial color like black or dark green for a two-tone effect.
Strap/Bracelet: Compatible with the Seikonaut integrated bracelet in rose gold. Standard spring bar attachment at the lugs.
Not compatible: 7S26 and 7S36 movements use a different stem height and are not recommended for this case.
What’s Included
- Seikonaut case body (316L steel, 20-micron rose gold PVD)
- Caseback (solid or exhibition, depending on variant selected)
- Screw-down crown with signed logo
- Crystal gasket and caseback gasket
- Sapphire crystal (pre-installed, clear or blue AR coating)
Tools are not included. You will need a case opener, hand press, stem cutter, movement holder, and rodico to complete your build.
Why We Chose This Case
Rose gold is one of the most requested finishes in the Seiko modding community, but most rose gold cases on the market use thin electroplating that wears through within months. The Seikonaut uses 20-micron PVD (Physical Vapor Deposition) for significantly better durability — the coating bonds at a molecular level rather than sitting on the surface. Combined with the ultra-thin 9.95 mm profile, the result is a rose gold Nautilus case that actually wears like a refined watch rather than a chunky mod. The brushed surfaces catch light differently from the polished accents, adding visual depth that flat plating cannot achieve.
Build Guide
Difficulty: Moderate — suitable for first-time builders with proper tools and patience.
Tools needed: Case opener (or case press), hand press or hand setting tool, stem cutter, movement holder, rodico, and tweezers.
PVD-specific tips:
- Handle with care: While PVD is durable in daily wear, metal tools can scratch the coating during assembly. Use rodico and plastic tweezers where possible.
- Stem cutting: Measure twice, cut once. Leave 0.5 mm extra and trim down gradually to avoid cutting too short.
- Gasket seating: Both gaskets must sit flat in their channels for the 50 m water resistance rating to hold. A twisted or pinched gasket will leak.
For full step-by-step instructions, see our complete Seiko mod build guide.
Frequently Asked Questions
Will the rose gold PVD coating wear off?
The 20-micron PVD coating is significantly more durable than standard electroplating. PVD bonds to the steel at a molecular level, so it resists daily wear, sweat, and minor scratches far better than plating. With normal use, the finish will hold up well over time. Avoid abrasive surfaces and harsh chemicals to maximize longevity.
What dial colors pair well with rose gold?
Rose gold pairs naturally with warm tones — champagne, salmon, and white dials create a cohesive luxury look. For higher contrast, black and dark green dials provide a striking two-tone effect. Our Rose Gold Nautilus Skeleton Dial was designed specifically to match this case finish.
What movements fit this case?
All standard Seiko NH-family automatics: NH35, NH36, NH38, NH70, NH71, and NH72. For a full skeleton look through the exhibition caseback, use the NH72 skeleton movement. The NH72’s golden bridges complement the rose gold case beautifully.
Complete Your Build
- Rose Gold Nautilus Skeleton Dial (30.8 mm) — matching rose gold tone, purpose-built for this case
- Rose Gold V2 Nautilus Hands — brushed rose gold hands to complete the look
- Seiko NH35 Movement — reliable workhorse movement for a solid daily-wear build
- Seiko NH72 Skeleton Movement — golden bridges that match the rose gold case finish
Browse Collection
Nautilus-Style Seiko Mod Parts · All Seiko Mod Cases · Nautilus Seiko Mods
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