“While the El Primero movement appeared in three models – A384, A385 and A386 – other important early adopters of the legendary calibres came on the market, including the rare reference A3818, one of the rarest El Primero references, with about 1,000 examples produced. This specific watch, known for its blue dial with a “shark tooth” chronograph scale, earned the nickname “Cover Girl” after appearing on the front of Manfred Rössler’s book Zenith: Swiss Watch Manufacture Since 1865.” Cheers Marc