Valjoux 7730

Hand-wound dual-register chronograph movement produced from 1966 to 1973. Originally the Venus 188 (produced 1948-1966), renamed when Valjoux absorbed Venus. Features a small seconds subdial at 9 o'clock, 30-minute counter at 3 o'clock, and central chronograph seconds. Uses a cam-switching (coulisse lever) system rather than column wheel, making it more affordable. The movement helped democratize the chronograph during the mid-century era. Used by Heuer, Breitling, Hamilton, Zodiac, and many others.