Calibre 520⚙️ 15 jewel ⚙️ 18,800 A/h ⚙️ 1941 The Calibre 520 was the first movement produced by Eterna for men’s wristwatches. It beats at 18,000 BPH and had a power reserve of 42 hours. This service watch is still beating accurately even through all its time out in the
