Ultrathin Tourbillon Onyx (Platinum)

The Arnold & Son Ultrathin Tourbillon Onyx Edition is a haute horlogerie timepiece distinguished by its extreme thinness, refined finishing, and innovative use of ornamental stone. Housed in a 41.5 mm case crafted from either 18-carat 5N red gold or 950 platinum, with an overall thickness of just 8.40 mm, the watch showcases a deep black onyx dial that contrasts a polished main surface with a concave, matt-finished onyx hours and minutes sub-dial—an unprecedented treatment in watchmaking.

At 6 o’clock, a wide aperture reveals the one-minute flying tourbillon, whose large, delicately finished cage features symbolic elements inspired by John Arnold’s marine chronometers. Driving the watch is the in-house, manually wound calibre A&S8300, measuring only 2.97 mm thick, operating at 3 Hz, and offering an impressive 100-hour power reserve thanks to a twin-barrel construction. Visible through the sapphire case back, the movement is finished to the highest standards with hand-polished and chamfered bridges, radiating Côtes de Genève, blued screws, and a hand-engraved 3N yellow gold tourbillon bridge. Completed by a black alligator leather strap with folding clasp, the Ultrathin Tourbillon Onyx Edition is produced in a strictly limited series of eight pieces per metal, affirming its status as a highly exclusive contemporary tourbillon.