Our reusable Drop in Filter is designed to be the last air filter you buy for the car. It can be cleaned and reused and provides exceptional filtration for your engine. It fits in your OEM air box and replaces the factory filter. Performance is increased as the cotton gauze media filters but does not impede air flow. These filters do not require oil so it does not clog your maf sensor throwing a CEL. Fit 15-18 BMW M3 15-19 BMW M4 13-16 BMW M5 12-18 BMW M6 14-19 BMW M6 Gran Coupe