The Pro 5R Filter has five layers of oiled filtration media and is reusable. The Pro Guard 7 Filter has seven layers of oiled filtration media, and is also reusable. The Pro 5R is designed for general-purpose performance and general driving applications, and offers slightly increased levels of airflow over aFe's Pro Dry S and Pro Guard 7 filters, while still having improved filtration over stock. The Pro Guard 7 is built for extreme-duty applications with high levels of dust, grime and pollution, and has the most efficient filtration out of aFe's air filters, though at the expense of not flowing air quite as effectively.