Porsche Air Duct 911 95 98 993 106 402 02 91109593220027 These race proven compact alternators Option:Without Access Holes These race proven compact alternators offer the best size and power weight ratio available and at far lower rpm than alternatives due to their patented design which enables them to offer up to 80% of maximum output at average idle speeds catering for the large electrical loads usually found at this time ensuring optimal performance and protection Aerodynamics: Contributes to improved aerodynamics by smoothing the airflow underneath the vehicle An Air Duct is a protective panel that covers the underside of an engine