Audemars Piguet Releases Three New Royal Oak Double Balance Wheel Openworked Models Arriving in black ceramic, stainless steel and 18-carat yellow gold. Audemars Piguet has quietly added three new Royal Oak Double Balance Wheel Openworked models to its roster of luxury watch offerings. Boasting a 41mm case size, the new time-tellers are offered in three different materials, namely black ceramic, stainless steel and 18-carat yellow gold, each complete with a matching integrated bracelet. The watch case proudly showcases its sophisticated and intricately crafted skeletonized 3133 caliber — a self-winding movement that powers the piece continuously for 45 hours, while beating at 21,600 vibrations every hour.