New moon

Watch news and tools for
collectors and the curious.

Accuracy

How many seconds a day your watch gains or loses, heard through your phone’s microphone.

Jacob & Co. Billionaire Double Tourbillon Double Tourbillon BL140.30.BD.AA.A
Jacob & Co. · BL140.30.BD.AA.A

Billionaire Double Tourbillon Double Tourbillon

Change

Somewhere quiet, lay the watch caseback up on something soft. Rest the bottom edge of your phone on the caseback and keep both still.