1973 Zenith El Primero Surf Ref. 20.0220.416 **Maker:** Zenith **Model:** El Primero Surf **Reference:** 20.0220.416 **Year:** 1973 **Material:** Gold electroplated stainless steel **Dimensions:** 36mm case, 19mm lug width **Crystal:** Mineral **Caliber:** Zenith Cal. 3019PHC, 31 Jewels, 36000 Vph **Strap:** Zenith crocodile leather strap with butterfly clasp **Box/Papers:** No **Price is** $2550 **OR YOUR BEST OFFER** **Shipping** out of Kuala Lumpur via FedEx **Payment** via Wise, PayPal F&F (G&S fees borne by buyer) Happy to provide references upon request. A first on WatchExchange, I’m offering this rare 1973 Zenith El Primero made for the US market in 1000 pieces only (Source: Zenith: Swiss Watch Manufacture Since 1865, Manfred Rössler). A highly unusual size for a chronograph, the 36mm case features a sought after C-shape design. Beating inside at a remarkable 36,000 vibrations per hour is the legendary Cal. 3019PHC (currently in manufacture as Cal. 400), first released by the Swiss brand in 1969 to compete against Seiko in the race for the world’s first automatic chronology movement. Till this day, the high beat Cal. 3019PHC (Cal. 400) is the only movement that can measure 1/10 of a second, thanks to its 36,000 oscillations. **Notes** This Zenith El Primero is in overall good condition. There are minor dings which is consistent with a watch of this age. The case is nice and unpolished, reflecting some minor gold plating fade on the pushers and sides. The original Zenith signed crown clicks in and out smoothly. The dial is in excellent condition, featuring tritium lume which still glows faintly. The watch comes fitted on an Zenith branded 19mm leather strap. The Cal. 3019PHC movement keeps superb time. The chronograph function works smoothly, with the pushers clicking solidly. View chronograph video demonstrating start, stop and reset functions at [https://imgur.com/a/wMwWvsf](https://imgur.com/a/wMwWvsf)