Experienced divers had drawn IWC's attention to a problem they faced and the company's engineers, who love nothing more than a challenge, set about solving it. The result of their efforts can be found in the Aquatimer Split Minute Chronograph, which features a flyback mechanism that works independently of the chronograph. This additional split-minute function is the only one of its kind in the world. It can be switched on and off at any time under water and enables the user to time another action - apart from overall dive time - such as an ascent or the length of a decompression stop. A rugged little rocker switch on the left-hand side of the case makes the mechanism easy to activate. The inside, too, is packed with top-quality features that include a mechanical, self-winding chronograph with aggregate timing up to twelve hours and the characteristic rotating inner bezel. This is adjusted using the chronograph reset button, which also functions as a crown. The impressive flagship of the Aquatimer fleet, with its imposing 44-mm diameter case, is available exclusively in titanium.