This replica Big Bang 5181 45mm pairs a King Gold case with Hublot’s signature sandwich construction and a dark dial that lets the warm metal do the talking. The 441.OX.5181.RX reference sits in the Unico family, carrying the in-house column-wheel chronograph caliber visible through the skeletonized dial. At 45mm with King Gold construction, this is a watch that prioritizes presence and mechanical exhibition over understatement.

Technical Overview

• Case diameter: 45mm
• Case material: King Gold (proprietary 18K rose gold alloy)
• Bezel: King Gold with six titanium H-shaped screws
• Crystal: sapphire with anti-reflective treatment
• Dial: skeletonized, exposing Unico movement architecture
• Strap: structured rubber with gold-tone clasp
• Movement: automatic chronograph (Unico platform)
• Functions: hours, minutes, chronograph, date at 3 o’clock

The Unico chronograph movement features a flyback function and a column wheel positioned on the dial side, visible through the open-worked upper layer. Power reserve sits around 72 hours on the genuine caliber platform.

Inside the Movement

What separates Unico-based references from the standard Big Bang lineup is mechanical ambition. The column wheel chronograph sits under the dial rather than hidden behind the caseback, making the entire timing mechanism part of the visual design. Through the skeletonized openings you see the chronograph lever, reset hammer, and column wheel teeth operating in sequence. The diamond-set 441.RX.1170.RX.1704 uses the same Unico platform in a very different aesthetic context. Browse the full Big Bang range to compare how different case materials change the same fundamental architecture.

What Sets It Apart

King Gold Unico references occupy the top tier of the Big Bang hierarchy. The precious metal case transforms what is already a large, mechanically expressive watch into something that commands a room. The dark dial and rubber strap provide enough contrast to prevent the gold from reading as overly formal, keeping the piece firmly in sport-luxury territory. Chronograph pushers at 2 and 4 o’clock maintain the characteristic Big Bang silhouette. This replica Big Bang 5181 45mm puts the full Unico chronograph experience inside a case material that signals investment-level commitment to the collection.