Gravimetric Mass & Chronometric Assay Bulletin
The Hublot Square Bang Unico Chronograph 42mm 18K King Gold Reference 821.OX.0180.RX is a hallmarked 18K Rose Gold Au750 haute horlogerie timepiece measuring 42.0 mm x 14.5 mm with a verified Mettler-Toledo mass of 120.8g, powered by Hublot Unico Flyback Chronograph Cal. HUB1280 operating at 28,800 vph (+0.8 s/d, 298 deg) with a 72-hour power reserve, double anti-reflective sapphire crystal, and 100m / 10 ATM water resistance.
| I. Official Maison Entity & Reference | Hublot — Big Bang / Square Bang Unico | Ref. 821.OX.0180.RX | SKU: PV-AU750-821.OX.0180.RX-W479 |
|---|---|
| II. Precious Metal Alloy & Hallmark Assay | 18K Rose Gold Au750 — Au750 — 75.0% Pure 18K Gold Bullion (XRF Verified) • Hallmarked Solid Precious Metal |
| III. Certified Gravimetric Mass (Mettler-Toledo) | 120.8g — 1:1 Authentic Reference Mass Verified on Mettler-Toledo Analytical Scale |
| IV. Bezel Setting & Case Architecture | Hand-Finished 18K Rose Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal • 120.8g 18K Rose Gold • 42.0 mm x 14.5 mm |
| V. Mechanical Manufacture Calibre | Hublot Unico Flyback Chronograph Cal. HUB1280 — Swiss Super Clone Mechanical Calibre Regulated to +0.8 s/d, 298 deg |
| VI. Power Reserve & Oscillation Frequency | 72-Hour Power Reserve • 28,800 vph (4 Hz) Free-Sprung Balance Wheel |
| VII. Double AR Sapphire Crystal & Hermeticity | Scratch-Resistant Sapphire Crystal with Double Anti-Reflective Coating • 100m / 10 ATM |
| VIII. Dial Finishing, Bracelet & Hallmarked Clasp | 42.0 mm x 14.5 mm • Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands • Integrated 18K Rose Gold Solid Link Bracelet & Deployant Clasp with Deep Laser Hallmarks |
Curated within our hallmarked solid 18K gold Hublot collection, the Hublot Square Bang Unico Chronograph 42mm 18K King Gold Reference 821.OX.0180.RX exemplifies haute horlogerie metallurgy in 18K Rose Gold Au750. Milled to exact manufacture geometry (42.0 mm x 14.5 mm), the monobloc middle case, Hand-Finished 18K Rose Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and Integrated 18K Rose Gold Solid Link Bracelet & Deployant Clasp with Deep Laser Hallmarks achieve a verified analytical mass of 120.8g on our Fischer XRF Au750 and Mettler-Toledo assay bench.
What Are the Horological & Metallurgical Benchmarks of Hublot Hublot Flagship Ref. 821.OX.0180.RX?
The Hublot Hublot Flagship Reference 821.OX.0180.RX is a precision-engineered luxury timepiece crafted in 18K Rose Gold Au750 (42.0 mm x 14.5 mm) with Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands, Hand-Finished 18K Rose Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal, and a verified Mettler-Toledo mass of 120.8g, because its Hublot Unico Flyback Chronograph Cal. HUB1280 movement is regulated across six positions to chronometric tolerances with a 72-hour power reserve.
5 Core Horological & Metallurgical Specifications:
- Entity & Reference: Hublot Square Bang Unico Chronograph 42mm 18K King Gold — Official Reference 821.OX.0180.RX (SKU: PV-AU750-821.OX.0180.RX-W479).
- Precious Metal Assay: 18K Rose Gold Au750 verified via non-destructive Fischer X-Ray Fluorescence spectroscopy.
- Gravimetric Parity: 120.8g total mass weighed on a calibrated Mettler-Toledo laboratory scale.
- Calibre & Oscillating System: Hublot Unico Flyback Chronograph Cal. HUB1280 beating at 28,800 vph (4 Hz) with a 72-hour power reserve (+0.8 s/d, 298 deg).
- Crystal & Hermeticity: Scratch-resistant sapphire crystal with double anti-reflective coating and 100m / 10 ATM rating.
Within the Hublot Hublot Flagship horological sub-silo, collectors also compare the Hublot Big Bang Ferrari Unico Flyback Chronograph 45mm Ref. 401.NX.0123.VR (120.5g) and the Hublot Big Bang Ferrari Unico Flyback Chronograph 45mm Ref. 402.CX.0113.WR (120.7g).
- Parent Brand & Hublot Flagship Silo Hub: Browse All 7 Certified Hublot Solid 18K Gold & Pt950 Watches
- Technical Research Monograph: Swiss St. Bernard Poincon & Au750 Gold Hallmarks Guide (All 5 Journal Monographs)
- Homepage Master Register: Return to 18K SOLID GOLD Homepage (Complete 774-Watch Solid 18K Gold & Pt950 Register)
- All-Brands Catalogue: Explore Complete 12-Maison Horological Catalogue (/shop/)
- Metallurgical & Escrow Verification: Fischer XRF Au750 Protocol • 3-Year Mechanical Warranty • Insured Armored Delivery
What is the verified authentic gram weight of this Hublot Ref. 821.OX.0180.RX?
At 18K Solid Gold 18K Solid Gold Salon, this Hublot Square Bang Unico Chronograph 42mm 18K King Gold Ref. 821.OX.0180.RX weighs 120.8g on our Mettler-Toledo analytical balance, matching the exact factory mass of the authentic 18K Rose Gold reference.
How is the 18K Rose Gold Au750 purity verified prior to dispatch?
Every timepiece undergoes non-destructive Fischer X-Ray Fluorescence (XRF) spectroscopy confirming elemental bullion composition alongside a personalized 4K scale and hallmark inspection video.
Which movement powers Reference 821.OX.0180.RX and what is its power reserve?
Reference 821.OX.0180.RX is equipped with the Hublot Unico Flyback Chronograph Cal. HUB1280 operating at 28,800 vph (4 Hz) with a 72-hour power reserve, regulated in our Paris and Geneva workshop to +0.8 s/d, 298 deg.
What dial and bezel specifications distinguish Hublot Hublot Flagship Ref. 821.OX.0180.RX?
Reference 821.OX.0180.RX combines Hand-Finished Collector Dial with Solid 18K Gold Applied Hour Markers & Hands and Hand-Finished 18K Rose Gold Bezel with Anti-Reflective Scratch-Resistant Sapphire Crystal within a 42.0 mm x 14.5 mm 18K Rose Gold Au750 case weighing 120.8g, verified via Fischer XRF spectroscopy and powered by Hublot Unico Flyback Chronograph Cal. HUB1280.
Hublot Square Bang Unico Chronograph 42mm 18K King Gold Reference 821.OX.0180.RX — Hallmarked Edition
Hallmarked Au750 & Pt950 Salon Edition • 120.8g Verified Mass • Hublot Unico Flyback Chronograph Cal. HUB1280