Original factory replacement high-flow air filter for BMW M series high-performance models (M2/M3/M4/M5/M6/M6 Gran Coupe). With a four-layer viscous cotton fabric medium, it achieves a balance between precise filtration and high intake efficiency. It supports repeated cleaning and regeneration, and does not require modification to enhance the power response and throttle sensitivity of the inline six-cylinder / twin-turbo V8 engine. It is compliant and does not affect vehicle warranty.