The world’s most popular and highest selling luxury watch brand produces a wide array of famous models: the Submariner, Gmt-master II, Daytona, Datejust and Day-date. Rolex introduced every one of these models more than 50 years ago and has been extremely conservative with changes to its original designs. Some customers like the steel models, while others prefer the costlier versions in precious metals with diamond accents. Rolex builds all of its movements in-house, continuously seeking improvements while carrying out basic, fundamental research. Among other developments, the brand has created its own alloy for hairsprings.