Offering a view of the beating heart of the El Primero Presented in a sleek 39. 5mm steel case Blue tricolour dial with a transparent running seconds counter Measures and displays elapsed time with 1/10th of a second precision Driven with precision by the iconic El Primero 3604 movement A GLIMPSE OF THE MOVEMENT WITHIN Bridging the past and present, the Chronomaster collection embodies the brands mastery of automatic, high frequency chronograph movement and the unique design language established over the course of 50 years. The Chronomaster Open exposes the beating heart of the El Primero movement in an unexpected way. THE HEART OF PRECISION Revealing the iconic movement hard at work within, this striking model features an open base plate and bridges, as well as an escape wheel and pallet lever crafted in lubricant-free silicone. Sitting confidently within a 39. 5mm steel case, the blue dial makes a bold statement with three counters - a 60-minute counter at 6 oclock, 60-second count