The Rolex fluted bezel is a mark of distinction. Originally, the fluting of the Oyster bezel had a functional purpose: it served to screw the bezel onto the case helping to ensure the waterproofness of the watch. It was therefore identical to the fluting on the case back, which was also screwed onto the case for waterproofness, using specific Rolex tools. Over time, the fluting became an aesthetic element, a genuine Rolex signature feature. Today the fluted bezel is a mark of distinction, always in gold. Gold is coveted for its lustre and nobility. Steel reinforces strength and reliability. Together, they harmoniously combine the best of their properties. A true Rolex signature, Rolesor has featured on Rolex models since the early 1930s, and was trademarked as a name in 1933. It is one of the prominent pillars of the Oyster collection. The Sky-Dweller is fitted on a solid-link Oyster bracelet in Oystersteel, in the case of the white Rolesor version, or, for the yellow Rolesor version, an Oyster bracelet combining Oystersteel and 18 ct yellow gold. The Oyster bracelet benefits from the new concealed attachment system beneath the bezel which ensures seamless visual continuity between the bracelet and case. It is equipped with a folding Oysterclasp and also features the ingenious Rolex-patented Easylink rapid extension system that allows the wearer to easily increase the bracelet length by approximately 5 mm, for additional comfort in any circumstance.