Nomods Solid caseback / Clear AR Rose Gold Seikonaut Seiko Mod Case – NH35/NH7X (Ultra-Thin)
Nomods Exhibition caseback / Clear AR Rose Gold Seikonaut Seiko Mod Case – NH35/NH7X (Ultra-Thin)
Nomods Seikonaut / Nautilus Style Seiko Modding Case Ultrathin Rosegold

Seikonaut 40mm Case – Rose Gold

Regular price$149.00
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The Seikonaut case is engineered as a slim, well-proportioned foundation for Seiko modding. At just 9.95 mm with a solid caseback, it’s among the thinnest Nautilus-style cases available, achieved through tight internal tolerances and precise CNC machining in 316L stainless steel. An integrated-lug silhouette, sapphire crystal with optional AR coating, and a screw-down crown complete a case designed to sit close to the wrist while remaining practical and easy to build with.

Caseback
Anti-Reflective Coating
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Complete Your Build

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 low-profile 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
  • 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.

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.

Seikonaut 40mm Case – Rose Gold
Seikonaut 40mm Case – Rose Gold
$149.00

Seikonaut 40mm Case – Rose Gold
Others
Premium 316L Stainless Steel
Sapphire Crystal Glass
30-Day Money Back Guarantee
20-Micron Thick Plating
Ultra-Thin Case Design
Anti-reflective coating
Strict Quality Control
Built to a Higher Standard
Choose quality and precision. Choose Nomods.

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Frequently Asked Questions

Use this section for any descriptive text you need to fill out your pages or to add introductory headings between other blocks.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

A Seiko mod is a custom watch built using a Seiko or NH movement combined with aftermarket parts such as cases, dials, hands, and crystals. Mods can be bought prebuilt or created by DIY modders.

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