Moreover, these are the tool watches used by professional divers, not many are available to people who are non divers. These were sold in the professional diving equipment companies and therefore has limited circulation. In addition, as a result of its small circulation, be prepared that the parts such as the hands, bezels etc may have been switched as the owners (Not collectors) then were not particular of the state of so called originality of the watch as long as it was usable and functioning. My ZRC Spartiale is a NOS in full original mint condition while my series 2 had the hands changed. As a vintage watch collector, I am fine with these changes as if anyone wants all perfect watch should get a re-issued ZRC instead. One way is try to find NOS spare parts for them, which is a fun and challenging project.
Later, I ahve managed to find the ZRC Series 2 from France.