The aero package on McLaren's MP4-25 has caused quite a stir since its launch. Here's a brief explanation of how it works.

The airbox has two channels. The lower is designed to cool the gearbox radiator (large red arrow in picture). Here, hot air that is pushed out hits the rear edge of the lower beam wing and diffuser (small red arrows in picture).

The upper air channel pushes air through the long fin that connects to the rear wing. The air is then directed on to the wing-flap, via a slot.

These two channels of air mix together and stall the rear wing at high speeds to mimise drag and raise the maximum speed that can be achieved.

A duct at the front of the chassis feeds additional air into the system to 'over-saturate' it and prevent it from functioning.

Drivers can operate the closing and opening of the duct with their left leg or arm to bring the system in to play on long straights, where the extra speed can be most effectively used.