This is a rare 18K rose gold Zenith Ref 550 from the early 1960s, with an uncommon pulsation dial running on a Zenith Caliber 146D movement.
We offer this watch in a beautifully preserved condition: the case shows hardly any signs of wear. The unpolished lugs are sharp and the serial numbers on the snap-back case are crystal clear. There are also two pristine hallmark behind the lugs, indicating that the watch was probably never polished.
The pulsation dial is excellent condition and is RARE for a Zenith chronograph of the period, because most of the watches in the 1960s came with tachymeter scales. The dial has a stunning sunburst pattern. It is completely original, and only shows light aging. The combination of the pulsation dial and 18K rose gold case is quite special on this piece.
The watch is equipped with Cal.146D, which has an interesting story of its own. It is a manual wind, nickel finished, column wheel movement of the highest quality, and was one of the last manual wind movements Zenith made before moving to the automatic El Primero platform.
Cal. 146 is based on the Martel Caliber 724: Martel was a manufacturer of high-grade chronograph movements and worked in close partnership with the Universal Watch Company in 1930s-1940s. The partnership developed some of the earliest two-pusher chronograph movements that Universal branded as “Compur” and “Compax”. In 1960, Zenith bought this long-time movement supplier and incorporated Martel’s technology “in-house”. Just two years after the acquisition, Zenith abandoned Martel to start research on the self-winding El Primero movement. Zenith never went back to manufacturing manually wound chronographs again.
This is a very high quality watch, with unusual dial features and an interesting story. We think it offers compelling value at this price.
Signed Zenith: case, dial, movement
Diameter: 36 mm
Winding: manual, column-wheel chronograph
Frequency: 18,000 vph
Power Reserve: 40 hours