Ca. Ø35mm, 18K gold, pressed back, case number 612318, Zenith punch, Swedish owner's engraving, chronometer movement calibre 135, signed, stripes decoration, fine adjusting device, movement number 4405018, perfectly preserved dial with pink gold numerals/indexes, marked Chronometre Zenith, pink gold hands, high-quality leather strap with buckle, in very good condition, in working order. In 1948, Ephrem Jobin introduced the legendary Zenith calibre for the first time, at a time when numerous watch manufactures werepeting in observatorypetitions to achieve greater precision. The calibre 135 produced several technical innovations that made it possible to achieve numerous awards and prizes in thepetitions, including an unprecedented succession of five consecutive prizes at the Neuchâtel Observatorypetitions between 1950 and 1954. In total, this type of movement achieved over 200 awards, two-thirds of them first prizes.