The Memovox Polaris, of which 1714 were made between 1965 and 1970, remains Jaeger-LeCoultre’s best known diving watch. The project took shape in the wake of the 1959 Memovox Deep Sea. The Manufacture’s new creation had an unusually large case for the time: 42 mm! One year after the launch of the first models, the Memovox Polaris was fitted with a new system to increase the volume of the alarm under water. A triple case back prevented the sound from being damped by the diver’s rubber suit. It consisted of an inner case in bronze for the resonance of the alarm, a waterproof back and an outer back with 16 round openings. Manufactured in 1967, the Memovox Polaris watch to be sold by Artcurial, model E859, is among the first models fitted with the patented Compressor triple back. It also offers an inner bidirectional rotating flange, luminescent hour-markers and hands and a date aperture. Composed of 241 parts, the self-winding Jaeger-LeCoultre 825 calibre is equipped with a hammer rotor. Although perfected over the years, today’s Jaeger-LeCoultre alarm watches still use a similar alarm system.