El Primero 3604

The El Primero 3604 1/10 th of a second automatic chronograph movement is a modified version of the 3600 that debuted in the CHRONOMASTER Sport, featuring an open base plate and bridges that allow for a clearer view of the high-frequency 5Hz escapement with lubricant-free silicon escape wheel and pallet lever. The automatic winding mechanism efficiently delivers a power reserve of 60 hours. Automatic El Primero column-wheel chronograph able to measure and display the 1/10th of a second Central chronograph hand that makes one turn in 10 seconds Increased power reserve of 60 hours Stop second mechanism Certified Chronometer