Also Existing over the dial and arms is Rolex’s Chromalight lume. This more recent in-household content was first launched in 2008 as Rolex’s proprietary luminescent compound and considering that its introduction, it's entirely replaced Super-LumiNova within the model’s lineup. Together with the highly corrosion-resistant 904L stainless steel (labeled as “Oystersteel” https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/