Sotheby's auction house in Hong Kong was the scene for some frenzied bidding on Saturday, when an exceptionally rare, and quite possibly unique, Rolex Daytona sold for more than three times its upper estimate. As part of the Important Watches sale at Sotheby's Hong Kong, the Cosmograph Daytona has a platinum case and a lapis lazuli dial. It is considered to be historically important as it is the only such chronograph to have appeared at auction; it could be the only one ever made by Rolex. A chronograph is a type of watch that is used as a stopwatch as well as a display watch. Offered by a private collector, the 40mm timepiece is powered by a 4030 Zenith automatic movement calibre. Zenith produced the movements for Rolex Daytonas between 1988 and 2000, after which Rolex switched to using its own in-house movement. Bearing the reference 16516, this timepiece is only the second known example to carry this number. The other is a platinum Daytona with a dial made of black mother-of-pearl; it was sold by Sotheby's at auction in 2018 for US$871,000 (Dh3.2m). At the time of that sale, Sotheby's wrote, "While Rolex produced automatic Daytonas only in stainless steel, yellow gold, white gold, and steel and gold, for many years, it has now been confirmed that one very lucky customer was given a unique masterpiece in 1999, and it is rumoured that the late Patrick Heiniger, the famous CEO of Rolex, himself wore a platinum automatic Daytona." The rare platinum case is inscribed on the back and dated XII 1998, making it what Sotheby's described as "historically important and possibly unique". The auction house also said it was an "exceptionally rare" watch. With a listed estimate of between HK$4m to HK$8m (Dh1.9m to Dh3.7m), after some vigorous bidding the final price far exceeded all expectations, at HK$25.3m. In total, the sale generated an impressive HK$117m. Although the sum paid for the watch is impressive, the highest figure ever paid for a Daytona was in October 2017, when Paul Newman's personal Paul Newman Daytona timepiece was sold by Phillips for US$17.7m.