Ca. Ø58mm, ca. 172g, original silver case with gold hinges, case and movement with matching numbers, tested observatory chronometer with lever escapement, signed and very well preserved enamel dial with 24-hour indication and power reserve indicator, blued steel hands, in very good condition, in working order. To our knowledge, this watch is the only known example of a Ulysse Nardin Observatory chronometer with a 24h dial. The watches with the extract of the Observatory Neuchâtel chronometer test in 1908.