From Mitsipedia

Innovative Vehicle Elecronic Control System (INVECS) III is the name Mitsubishi gives to it's Continuously Variable Transmissions (CVT). As with the previous INVECS II system, it can self-learn and adapt itself to a driver's style. Mitsubishi claims it offers a smoother drive and greater fuel economy.

As with all CVT transmissions, INVECS III provides an infinite combination of ratios between two points to provide the best possible gearing for all driving conditions. The software is calibrated so that the gearing allows the engine to run at its optimum speed for both economy and performance.

In vehicles with sports shift (tiptronic) INVECS III, the driver can select from a set of six ratios as though they are driving a clutchless manual.