Produced between 1951 and 1967, the reference 2508 features several ♑elements that differentiate it from more classic vintage time only pieces. Its larger 35mm diameter case manufactured by Taubert & Fils closely resembles the celebrated chronograph reference 1463, and the screw-down case back gives it a sportier feel on the wrist. It was Patek Philippe's first foray into the water-proof time-only wristwatch market. In addition, as the forerunner to the Ama൲gnetic references, it featured an innovative ’double case back’ design: a metal dust cap to keep moisture and magnetism at bay.