Subaru WRX/ STI Type RA Rear Bumper Ducts 2015-2021***Direct OEM Replacement on Subaru RA ONLY*** Excessive heat can cause major and expensive damage to critical components in a car. Engine bays, radiators, brakes, transmissions, and differentials all need good air flow to help transfer away unwanted heat. APR Fender Vents help reduce high pressure air that builds up in the wheel wells . Built using pre preg. carbon fiber reinforced polymer (CFRP) composite materials for superior strength to weight