Hacking Seconds

Definition

A stop-seconds function: pulling the crown to the setting position halts the balance wheel, so the seconds hand stands still and the watch can be set to a reference signal exactly. It began as a military requirement, for synchronising watches before an operation, and is now standard on most movements, though not all. The ETA 2824 behind the Breitling Caliber 17 hacks, as does every current Rolex caliber, and Omega added hacking to the Moonwatch only with the 3861 in 2019, after fifty years of the 861 and 1861 running without it. Many older hand-wound movements, including the Unitas 6497 family, were built without it.