For Nissan Maxiam Aluminum Cold Air Intake System (Silver)+3.5" Filter (Red) Helps engine to draw in more and colder air resulting in better throttle response and higher explosive horsepower output Improves up to 95% filtration efficiency Increases 5 to 10 horsepower, 6 to 8 precent of torque, and improve the gas mileage 3.5" inlet Air filter is micro cotton gauze type filter material, washable with water or soap, and reusable Fast-flow filter reduces airflow restriction and improves with aggressive sound