Laurent Ferrier and Urwerk joined forces to create the Arpal One, a piece-unique (one-of-a-kind) watch that will be on sale at the Only Watch 2017 charity auction in order to help finance research on Duchenne Muscular Dystrophy. The Arpal One is essentially an Urwerk designed by Laurent Ferrier, so it has rotating satellite wandering hours display that’s an Urwerk signature, but the case is a sleek construction reminiscent sof classic cars; Ferrier himself was once a racing driver who took part in the 24 Hours of Le Mans in 1979. The case was shaped from an exclusive alloy called ARPAL+, specifically developed for this unique watch. ARPAL+ consists of 75% precious metals and resists wear and scratches better than white gold or steel. Its colour never fades, nor does it oxidise. While the case is perfectly polished, the Urwerk’s movement is almost colourless. The four hours satellites are in a matt pearly grey with diamond-polished outlines while the hours and minutes markers are painted in white Super-LumiNova. The time is shown by four satellites, each bearing three hours numerals, which successively sweep past the track of minutes. This original and intuitive way of telling the time is aided by a cover in polyetheretherketone, a thermoplastic known as PEEK, which hides the satellites that are not engaged in indicating the time. The satellites turn on a hidden carousel, at the heart of the successive passage of the hours. Engineering the smooth and silent revolutions of a module that weighs 500 times as much as a conventional set of hands is one of the many challenges involved in the manufacturing of this movement. Beating at a frequency of 4 Hz (28,800 vph), the self winding UR5.03 is governed by a double turbine and offers a power reserve of 48 hours. The cabochon winding crown recalls the stripes of the satellite hours. The Arpal one is completed by a nice sand-coloured leather strap. The Arpal One will be sold at auction on November 11, 2017 at Christie’s in Geneva, alongside the four dozen other unique watches created for Only Watch 2017.