A watch that is as hard and scratch-resistant as diamond (9 on the Mohs scale, versus 10 for diamond) and as light as titanium, 107 grams on the wrist. Absolute transparency dressed by the sparkle of a solar yellow that extends all the way to its natural rubber bracelet lined with the colour yellow. Released in only 100 pieces, the Spirit of Big Bang Yellow Sapphire houses a self-winding skeleton chronograph movement, entirely "Hublotized" in its architecture and its finishing, from the legendary Zenith El Primero calibre.