The Aquatimer Chrono-Automatic combines two major advantages: that of the functional design created for diving and found in the original Aquatimer family, together with the additional benefits of a self-winding, mechanical chronograph that has been specially adapted to the unusually difficult conditions facing a diver?s watch. It was a challenge that IWC?s specialists mastered with aplomb. Here, too, the chronograph reset button at 4 o?clock has two functions. First, as the crown used to adjust the rotating inner bezel: this turns in only one direction and is indispensable for diving. And, second, as a button for the chronograph. When this dual-function button is pushed it automatically disengages the transmission wheel for the rotating bezel. All in all, then, the case of the superb Aquatimer Chrono-Automatic, which measures an imposing 42 mm in diameter and is water-resistant to 120 m, is packed with sophisticated technological features.