A stainless steel chronograph wristwatch with calendar, registers, tachometer and moon phases, Universal Genève, 'Tri-Compax', circa 1950

nickel lever movement, 17 jewels, mono-metallic compensation balance, black matte dial, baton numerals, apertures for day and month, four subsidiary dials indicating constant seconds, 30 minute and 12 hour registers and date combined with phases of the moon, circular water-resistant-type case with black bezel calibrated for tachometer, case, dial and movement signed.