The black dial includes rose gold-tone Arabic numerals, three-handed movement, and a date window sitting at 3 o'clock. The GMT subdial sits below 12 o'clock while the power reserve function sits above 6 o'clock and shows how much of the 40 hours of reserve power the automatic movement has remaining. Other features include a curved sapphire crystal for excellent scratch resistance and water resistance to 50 meters (165 feet)--suitable for swimming but not for diving.
An automatic (or self-winding) watch is fitted with a device (rotor) that automatically winds the spring by using the force of gravity. It needs no battery, but it will stop if you have been physically inactive for an extended period of time--as long as you're moving, the watch will stay powered. Swiss watchmaker Abraham-Louis Perrelet invented the self-winding mechanism in 1770. It worked on the same principle as a modern pedometer, and was designed to wind as the owner walked.