Pro 5R Air Filter by aFe. The Pro 5R air filter provides increased airflow to your engine without sacrificing filtration ability. The increased airflow allows your engine to make more power, and have better throttle response and fuel mileage. And with a 98.6Percent filtration efficiency rating, it outperforms most other cotton gauze media air filters on the market. Get the best of both airflow and filtration, with the aFe Pro 5R.