Zenith “El Primero-Aviateur”

Swiss Watch Fair 1972 BF 207
A flight model of the world 1s only high frequency chronograpt.
Turning bezel for computing flying times and tachymetric scale
specially for high speeds. All surfaces have been glareproofed. The case is guaranteed water-resistant to 0 atmospheres (a depth of 300 metres) Hour, minute and seconds registers. With calendar. (ZENITH “El Primero-Aviateur”)