This J-serial Audemars Piguet Royal Oak Double Balance Wheel Openworked Ref 15407ST.OO.1220ST.01 is new and unworn. The Royal Oak Double Balance wheel Openworked tackles stabilising issues by fixing a second balance wheel and balance-spring assembly on the same axis. The new patented geometry involves a very complex manufacturing procedure, but the payoff is huge: greatly improved precision and stability. It comes with box, green tag, booklet and warranty card dated in December 2017.
