Heuer Carrera Chronograph Cal. 12 Ref. 110.573 with Rare “Automatic” BoxIt is a well known story that in 1969, three automatic chronograph calibers were introduced: the Zenith "El Primero," Seiko's Caliber 6139, and, last but not least, the joint venture between Breitling, Heuer, Bren, and Hamilton, which produced the Caliber 11. These Caliber 11 movements were used in the Heuer Monaco, Carrera, and Autavia chronograph lines. Shortly after, these movements were improved to the Caliber 12, and that's exactly what we have