[WTS] Zenith El Primero ref. 01.0200.415 Big Blue 7000 run like hell circa 1973

Zenith El Primero ref. 01.0200.415 Big Blue circa 1973 The Zenith El Primero is a legendary high-frequency automatic chronograph movement first introduced in 1969. Its name, Spanish for "The First," reflects its status as one of the world's first integrated automatic chronograph movements.  Most mechanical watches beat at 4 Hz (28,800 vibrations per hour), but the El Primero beats at 5 Hz (36,000 vph). This allows it to measure elapsed time with a precision of 1/10th of a second. What doe this...