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This is a high‑quality generic replacement sapphire crystal for the Frederique Constant Slim Line reference 306S4S6B3, measuring 35.0mm (diameter) × 2.5mm (overall height) × 1.0mm (edge thickness) with a domed profile and a blue anti‑reflective (AR) coating. Made of synthetic sapphire glass (Mohs hardness 9), it offers exceptional scratch resistance and excellent optical clarity, serving as a direct substitute for a damaged or scratched original crystal.
Sapphire Crystal – Mohs 9, extremely scratch-resistant and optically clear.
Domed Profile – Classic curved shape, enhances the watch’s elegance.
Blue Anti-Reflective Coating – Reduces glare, improves dial visibility with a subtle blue tint.
Precise Dimensions – 35.0mm diameter, 2.5mm total height, 1.0mm edge thickness, fits original case groove.
Generic Aftermarket – Non-original but dimensionally accurate for 306S4S6B3; cost-effective.
| Parameter | Details |
|---|---|
| Compatible Model | Frederique Constant Slim Line 306S4S6B3 |
| Type | Generic (aftermarket, not genuine) |
| Material | Synthetic sapphire crystal |
| Shape | Domed |
| Diameter | 35.0 mm |
| Overall Height | 2.5 mm |
| Edge Thickness | 1.0 mm |
| Coating | Blue anti-reflective |
Q1: What is the difference between blue AR coating and clear AR coating?
A: Blue AR coating reduces glare while reflecting a subtle blue hue – a signature feature of many Frederique Constant Slim Line original crystals. Clear AR coating only reduces glare without the blue tint.
Q2: How to tell if the crystal has blue AR coating?
A: Tilt the crystal under a light. A vivid blue reflection indicates blue AR coating; white or pale yellow reflection means no blue coating. This product features blue AR coating.
Q3: Will the watch retain its original 30m water resistance after replacement?
A: Due to tolerances in generic parts, the original 30m rating cannot be guaranteed. Always perform a pressure test after installation. Treat as splash‑proof only.
Q4: Is a gasket included with this crystal?
A: No. Purchase a matching round gasket separately, and apply a thin layer of silicone grease before installation.
Fast worldwide shipping within 3 business days.
Competitive pricing on Seiko/Hattori calibers.
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