The Unico 2 caliber was designed to equip smaller chronographs and also open the world of Hublot to new enthusiasts. It retains the unique design of its former version with a double coupling system visible from the dial side as well as a 72-hour power reserve. But thanks to various technical optimizations, including the introduction of a new, flatter automatic winding system, it has been reduced by 1. 3 mm in thickness. Titanium 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.