Detailed features & specificationsHUB4700The HUB4700 caliber is the successor to the famous El Primero caliber a?? the first chronograph with an integrated style automatic winding (1969), which was also the first mechanical chronograph equipped with a 5 Hz frequency (36a??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.??TITANIUMTitanium is extensively used by Hublot, specifically for its lightness. It displays the best relationship between resistance and weight of any material, which makes it an extremely popular material especially within aeronautics. It also stands out with its resistance to corrosion and its inertia in contact with the skin. Hublot only uses high quality, grade 5 titanium, the strongest there is. Once polished, this material retains a slightly bluish metallic sheen.??Technical DetailsReference a?? 648.JX.0102.RT.MXM24Size a?? 42 mmCase a?? Polished Sapphire CrystalBezel a?? Polished Sapphire CrystalWater Resistance a?? 50m or 5 ATMCrystal a?? Sapphire with Anti-reflective TreatmentDial a?? Sapphire Crystal DialMovement a?? HUB4700 Self-winding Skeleton Chronograph MovementPower Reserve a?? 50 HoursStrap a?? White Structured Lined Rubber StrapsClasp a?? Titanium Deployant Buckle Clasp