



(c): Mars Mountain
ZENITH Quartz cal 51.0 (ESA 9181), ca 1973-1974. Features quickset day (in German) and date. The ESA 9181 was ETA:s first quartz movement. Quartz @ 32.768 Hz controlling a stepper motor. Seven jewels. It does not have sweep seconds as stated on other sites.
This Zenith XL-Tronic has refererence number 01.0010.515, square steel case and a somewhat scratched mineral crystal. At 41 mm wide (excl. crown) and 12,6 mm thick it is a massive chunk of stainless steel on the wrist.