Active Autowerke Filter Replacement for Active Autowerke E46 M3 Supercharger KitThis is a replacement filter primarily for your Active Autowerke E46 M3 Supercharger Kit. Please confirm your filter size by measuring. This is an Active Autowerke Spec Green Filter. Key Features: Green High Performance Air Filters are uniquely designed to take full advantage of cottons capabilities. Unlike multi layer gauze filters which can fray and release fiber particles into your engine, Green Filter USA uses two layers of tightly interwoven