Accuracy
How many seconds a day your watch gains or loses, heard through your phone’s microphone.
Hermès · Arceau Petite Lune Jeté de diamants et saphirs
ChangeArceau Petite Lune Jeté de diamants et saphirs
Somewhere quiet, lay the watch caseback up on something soft. Rest the bottom edge of your phone on the caseback and keep both still.