Air Filter Audi A3 S3 TT VW Golf A1858Ryco Air Filters have excellent dust holding properties to retain dust within the media's 'tortuous path'. Ryco's design philosophy is to meet the vehicle manufacturers' performance requirements. Subjected to stringent testing procedures through a dedicated filtration laboratory to ensure superior filtration. A superior performing air filter must excel in ALL 3 critical areas to be deemed fit to do the job: Efficiency, Life and Flow.