A bumper diffuser is a part of a car's bumper that helps redirect air flow underneath the vehicle, reducing drag and improving stability. Full definition
Have a body kit including front lip, side skirts, and rear bumper diffuser. (shoppok.com)
Not all of it is for show, with the rooftop spoiler and below - bumper diffuser at the rear of the vehicle improving aerodynamics as well as aesthetics. (kbb.com)
Special aerodynamic features include a full front and side aero kit, rear deck wing and a lower rear bumper diffuser with an integrated center exhaust system. (hondanews.com)