|Diameter:||39.75 mm (17.67 ligne)|
|Complications:||2-Button, 6-Column Chronograph, Chronograph, Column Wheel Chronograph, Split Seconds Chronograph|
|Production: 1910 –|
Valjoux Cal. 20 is a pocket watch column wheel chronograph movement. Introduced around 1910, it was produced at least through the 1920s. It featured a six-column wheel to control the chronograph function. The chronograph used a central seconds hand with split seconds and a 30 minute counter. It was a dual-pusher design.