the movement.
"Originally designed for marine chronometers and deck watches in the 1950s, the pocket watch–size 5011 series is perhaps the most accurate series of movements the brand has ever produced, and some were entered into the last chronometer competitions in the 1960s"
"The 5011 movement received an award in by the Neuchatel Observatory for being the most accurate chronometer ever"
Yes, a vintage inhouse Zenith movement used in an modern very limited watch ( they only had a few hundred movements left. Some )
Just like Panerai had the 21 with a vintage Rolex movement and the 203 with a vintage Angelus.
But this 5011 is afcourse an inhouse movement from the 1960's