Window deflector

A pickup truck with deflectors on all door windows

A window deflector is mounted above the doors of some automobiles, to protect the inside of the car from rain or other precipitation in case of slightly opened windows. Additionally, it may help to prevent precipitation entering the interior in case of an opened door, e.g. dropping from the roof or directly from the air. Deflectors are also fitted to sunroofs to deviate wind.

It is also known as a "monsoonshield" or a "rain visor" (in countries without monsoon).

The primary purpose of window deflectors is to prevent dust, snow, rain, other precipitation or excessive wind from entering to the cabin. Also, window deflectors direct air flows over the vehicle, and thus, reduce the wind noise when driving on moderate speeds. Window deflectors can be installed directly in the window channel or attached to the vehicle's body in the sunroof or side window area using 3M automotive-grade adhesive tape. Window deflectors are common accessory in the automotive aftermarket. Being vehicle-specific, they are normally designed to fit individual car, truck or SUV models.

Rear window deflectors

An AMC Gremlin with a rear deflector

Rear window deflectors form a separate class of deflectors, as they are intended particularly for pickup trucks, SUVs, and other vagon-shaped vehicles. Rear window deflectors^[1] reduce the intensity of sun beams that stream through the tailgate windows and cause interior overheat.

Carbon fiber window deflectors

Carbon fiber window deflectors are stronger than traditional plastic window guards, as carbon fiber strength is comparable to metal, while maintaining the lightness of plastic. They are in high demand for off-road vehicles, trucks and jeeps, where ruggedness and strength are necessary but metal too heavy and plastic too weak. Beast Carbon Co. is currently pioneering the production of window deflectors made with genuine carbon fiber.^[2]

References

1. "Rear Window Deflectors - Made To Shade Your Truck's Back Glass".
2. "Beast Carbon Fiber Window Guards for Trucks and Jeeps". beastcarbon.com. Retrieved 2016-10-24.