The Rolex Sky-Dweller is unique because it is the only Rolex model that comes with both an annual calendar as well as a GMT function (which keeps track of two timezones) for the active traveler.
Here's a list of the functions of the Sky-Dweller:
Dual Time Zone
The calendar function allows the Sky-Dweller to keep the date throughout the year, which means that the watch knows when to display a month with 30 days versus 31 – pretty cool, huh? All the main functions of the Rolex Sky-Dweller are also are accessed via a “Ring Command,” which means that its bezel is first rotated to different positions (to select the month, date, or time) and then the crown is turned to specify the desired value of the functions being accessed.
The 42mm Sky-Dweller is a solid piece as it pertains to the Watch Game. It's a heavy piece that is sure to raise your game to a higher level. You cannot go wrong with a timepiece like this regardless of the configuration you choose. As for me, one of my personal favorite Sky-Dwellers is the one in rose gold with a chocolate dial and a brown alligator strap. What a luxurious watch that is!
Rolex Sky-Dweller Men's 18k Rose Gold Annual Calendar GMT Watch 326935 - Automatic winding, perpetual calendar, and GMT feature. 18k rose gold case with fluted bezel (42mm diameter). Sundust dial with rose gold Roman numerals; date; second time zone; month indicator.