When driving a convertible with the top down, the force of air piling up against the windshield causes an increase in air pressure. Since the air pressure inside the cockpit is lower, when this air flows over the top of the windshield some of it seeks to equalize the air pressure difference. It does so by entering from the rear of the car into the cockpit.  A great illustration of this effect is the fact that hair actually swirls and blows forward, not backward, when driving with the top down.

 

The WindCheater™ physically blocks the back draft air currents from blowing into the cockpit, greatly reducing turbulence. You and your passenger can control air flow within the cockpit by adjusting the side windows and/or the WindCheater™.  With the side windows all the way up, the cockpit becomes more like a cabin with a giant sunroof.  You can actually adjust temperature with the heater or air conditioner, enjoy the sound system at reasonable volume and even hold a conversation in a normal tone.  The WindCheater™ allows you to extend your top down driving season and enjoyment, whatever your climate.