El Primero 3604

The El Primero 3604 is an automatic 1/10th of a second chronograph movement based on the 3600, featuring an open-worked base plate and bridges to showcase the 5Hz high-frequency escapement, which incorporates a lubricant-free silicon escape wheel and pallet lever. It provides a 60-hour power reserve via an automatic winding system and includes a stop-second mechanism, column-wheel chronograph functionality, and official chronometer certification.