The Porsche Doppelkupplung (PDK), with both manual gearshift and an automatic mode, enables smooth gear changes with no interruption in the flow of power. This results in significantly faster acceleration and lower fuel consumption, without having to sacrifice the ease of automatic transmission.
In total, PDK has seven gears at its disposal. Gears 1 to 6 have a sports ratio and top speed is reached in 6th gear. The 7th gear has a long ratio and helps to reduce fuel consumption even further.
PDK is essentially two half gearboxes in one and thus requires two clutches -- designed as a double wet clutch transmission.
Clutch 1 controls the first half gearbox, which contains the odd gears (1, 3, 5, 7) and reverse. Clutch 2 controls the second, which contains the even gears (2, 4, 6).