Seiko Premier Kinetic Perpetual SNP165 SNP165P1 SNP165P Quartz 100M Men's Watch The mecha-quartz complication is built with almost the same number of components as in any high-end mechanical, perpetual calendar watch, including the world's smallest, ultra-sonic motor. At just a mere 0.4 mm thickness, this ultra-sonic motor is the only motive energy for the mechanical gear trains that drive the Perpetual Calendar. There’s also a photo sensor built in to recognize a certain mark on each rotating component to keep the correct date, day, month and year, including leap years.