Accuracy
How many seconds a day your watch gains or loses, heard through your phone’s microphone.
Jacob & Co. · BU210.80.AM.UB.B
ChangeBugatti Chiron Tourbillon Sapphire Crystal Blue Sapphire Crystal with Rose Gold Backplate
Somewhere quiet, lay the watch caseback up on something soft. Rest the bottom edge of your phone on the caseback and keep both still.