This replica square bang 0170 42mm marks Hublot’s bold departure from curved cases into fully angular territory. The 821.HX.0170.RX uses the Square Bang Unico platform at 42mm, keeping the case compact enough for daily wear while preserving the geometric impact that defines this collection. The HX designation points to a mixed-material construction that pairs polished and brushed surfaces across flat planes rather than the curved transitions found on the Big Bang or Classic Fusion. At this size the Square Bang sits closer to a traditional watch footprint than you might expect from such an angular design.

Technical Overview

• Case diameter: 42mm square cushion
• Reference: 821.HX.0170.RX
• Case material: mixed composite with polished and satin finishing
• Crystal: sapphire with AR coating
• Movement: Unico automatic chronograph
• Functions: chronograph, date, flyback
• Strap: structured rubber with deployment clasp

The squared-off lugs and flat bezel screws give the 821.HX a distinctly architectural character. Each edge meets at a precise angle, creating light reflections that shift dramatically as you move your wrist through different positions.

Inside the Movement

The Unico caliber visible through the sapphire caseback drives a column-wheel chronograph with flyback function. Start, stop, and reset happen through pushers integrated into the case sides rather than traditional round pushers. The skeletonized dial exposes the movement architecture from the front as well, letting you see the chronograph mechanism engage in real time. Compare this open-dial approach against the black-dial 821.HX version where the darker treatment shifts visual emphasis toward the case edges. Both sit within the Square Bang collection but deliver very different wrist impressions depending on how much movement visibility you prefer.

What Sets It Apart

Square cases demand precise manufacturing because any misalignment along flat surfaces becomes immediately visible. The 821.HX.0170.RX handles this challenge with clean panel joins and consistent edge beveling across all four sides. Where round watches hide tolerance variations behind curves, the Square Bang puts finishing quality on full display. This replica square bang 0170 42mm rewards anyone who appreciates geometry-driven design executed with watchmaking discipline.