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This is a generic case back sapphire crystal designed for the Hublot Big Bang Unico model 411.NM.1170.RX, measuring 31.0mm in diameter and 1.7mm in thickness, featuring a flat round shape with blue anti-reflective coating. This watch is powered by the HUB1242 automatic chronograph movement, and the exhibition case back design allows viewing of the intricate movement mechanics. As a generic replacement for the original case back crystal, it is ideal for replacing damaged or deeply scratched original components.
| Feature | Description |
|---|---|
| Compatible Model | Hublot Big Bang Unico 411.NM.1170.RX |
| Location | Case Back Exhibition Window |
| Dimensions | 31.0 mm diameter × 1.7 mm thickness |
| Shape | Flat Round |
| Coating | Blue Anti-Reflective (AR) Coating |
| Material | Synthetic Sapphire |
| Hardness | 9 on Mohs scale – extremely scratch-resistant |
| Function | Protects movement, displays HUB1242 movement mechanics, maintains water resistance |
| Instruction | Details |
|---|---|
| Location Note | This crystal is installed in the exhibition window at the center of the case back to display the HUB1242 movement |
| Daily Use | No daily operation required after installation; normal wear is fine |
| Cleaning | Gently wipe with a soft cloth and mild soapy water; avoid abrasives or strong chemical solvents |
| Coating Feature | Blue AR coating reduces reflection and improves movement viewing clarity |
| Precautions | Sapphire is hard but brittle; avoid strong impacts to prevent shattering |
| Regular Inspection | Annual inspection for cracks or aged seals is recommended |
| Step | Instruction |
|---|---|
| 1. Remove Case Back | Use a professional case back opener (e.g., Bergeon 5700 series) to open the case back |
| 2. Remove Old Crystal | Carefully press out the old sapphire crystal from inside the case back |
| 3. Clean Groove | Thoroughly clean the crystal mounting channel inside the case back |
| 4. Inspect Gasket | Check the case back sealing gasket; replace if aged or damaged |
| 5. Place New Crystal | Place the new sapphire crystal into the mounting channel with flat side outward and blue coating facing the movement side |
| 6. Press Into Place | Use a crystal press with appropriate nylon dies to apply even pressure and press the crystal into place |
| 7. Check Installation | Verify the crystal is flush and free of gaps |
| 8. Reassemble Case Back | Reinstall the case back, tighten screws, and test water resistance |
| Aspect | Guidance |
|---|---|
| Cleaning | Gently wipe with a soft cloth and mild soapy water; avoid abrasives or strong chemical solvents |
| Scratch Removal | Sapphire crystals cannot be polished; deep scratches require crystal replacement |
| Coating Protection | The blue AR coating is delicate; avoid abrasive cloths or chemical solvents |
| Water Resistance Test | Perform a water resistance test after installation and annually thereafter to maintain 100m rating |
| Replacement Interval | Replace only if the crystal is cracked, deeply scratched, or the coating is damaged |
| Seal Inspection | Check the case back sealing gasket for aging during each service; replace if necessary |
Q1: Is this crystal compatible with Hublot Big Bang Unico 411.NM.1170.RX?
A: Yes, this crystal is specifically designed for the case back exhibition window of the Hublot Big Bang Unico model 411.NM.1170.RX. Please verify your original crystal dimensions before purchase.
Q2: What movement is inside the 411.NM.1170.RX?
A: The watch is powered by the HUB1242 automatic flyback chronograph movement, which features a column wheel, 72-hour power reserve, and 28,800 vph frequency.
Q3: What is the case diameter of the 411.NM.1170.RX?
A: The case diameter is 45mm (or 45.5mm depending on source), with a thickness of approximately 15.8mm.
Q4: What is the difference between overall thickness (1.7mm) and the crystal function?
A: The 1.7mm thickness is the total height of the crystal. As a flat round case back crystal, it is designed to sit flush with the case back while providing a clear view of the movement.
Q5: Does this crystal have anti-reflective coating?
A: Yes, this crystal features a blue anti-reflective (AR) coating on the inner surface to reduce glare and improve visibility of the movement, consistent with the original watch specifications.
Q6: Can I install this crystal myself?
A: A crystal press is absolutely required. The case back crystal installation requires careful alignment and even pressure. Professional installation by a watchmaker is strongly recommended to maintain water resistance.
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