At 45mm, this replica classic fusion 7170 45mm in reference 521.NX.7170.LR sits at the top of the Classic Fusion size range for time-only and chronograph models. The “521” prefix and 45mm diameter indicate a chronograph variant, adding timing capability through subdials at three, six, and nine o’clock that the smaller time-only 541 and 542 references lack. Titanium construction through the “NX” designation manages the weight of the larger case diameter, preventing the 45mm from feeling cumbersome despite its substantial wrist coverage. A blue sunburst dial and leather strap pair elegance with the expanded functionality of the chronograph complication.

Build Details

• Reference: 521.NX.7170.LR
• Case diameter: 45mm
• Case material: titanium
• Dial: blue sunburst with chronograph subdials
• Crystal: sapphire
• Strap: leather with deployant clasp
• Movement: automatic chronograph
• Functions: hours, minutes, seconds, chronograph, date

The three-register chronograph layout follows the standard arrangement that allows elapsed-time measurement up to 12 hours alongside continuous seconds and a 30-minute totalizer.

What Collectors Notice

The 45mm chronograph occupies the flagship position within the Classic Fusion time-only and chronograph hierarchy. Collectors tracking the 521 series recognize the size increase as necessary to accommodate the chronograph pushers and subdial layout without crowding the dial. The hublot classic fusion 45mm chronograph in titanium maintains a lighter-than-expected feel despite the additional mechanical complexity over the smaller models. For a non-chronograph alternative in the same titanium material, the 525.NX.0170.LR strips the dial back to a cleaner presentation. Both share a home in the Classic Fusion collection with titanium as the unifying element.

This vs Other Versions

Against the 42mm time-only references, the 521.NX.7170.LR offers more on the dial but demands more wrist real estate in return. The chronograph pushers at two and four o’clock add tactile functionality that time-only models cannot provide, appealing to buyers who value both form and stopwatch capability. The blue dial remains consistent in tone and sunburst quality with the smaller references, maintaining visual coherence across the size range. This replica classic fusion 7170 45mm delivers the largest and most functionally complete expression of the blue titanium Classic Fusion concept.