The HUB4700 caliber is the successor to the famous El Primero caliber - the first chronograph with an integrated style automatic winding (1969), which was also the first mechanical chronograph equipped with a 5 Hz frequency (36’000 alt/h) allowing an accuracy of 1/10th of a second. In a perfect fusion between tradition and innovation, this entirely skeletonized movement is now equipped with silicon regulating element ensuring avant-garde performances, precision and reliability. For Hublot, materials are an integral part of their watches’ design. They must complement their design, while protecting their mechanism and withstand the test of time. As such, the Manufacture has chosen to use high-tech ceramic for certain bezels and cases; it is an ultra-tough and almost entirely scratch-proof material (apart from the diamond) with a base of zirconium sintered at very high temperatures. 50 Hours power reserve.