Roger Federer is the most famous of the many Rolex athlete ambassadors. He signed on with the brand in 2006, by which time he had tallied nine Grand Slam wins. Roger has hoisted 11 more trophies since then, all while wearing a Rolex on his wrist. Although he has been known to wear a Sky-Dweller, a GMT-Master II, and a Yacht-Master II, lately he has been wearing his two-tone steel and yellow-gold Datejust 41 with a slate-gray dial and Roman numerals ($11,950). The Datejust is a classic but is considered more sporty than the Day Date, which is only available in gold or platinum. It contains the automatic caliber 3235, with the Rolex-patented Chronergy escapement, made of magnetic-resistant nickel-phosphorus. It is a Rolex-certified Superlative Chronometer, which means it keeps time more accurately than the standard set by the Swiss Chronometer rating institute, known as COSC.