The aFe Inverted Replacement Filter (IRF) is constructed with 100% polyurethane on all sides. This high flow, oiled inverted replacement performance filter will out flow stock paper filter by 33% for improved horsepower and torque. This is the largest filter that can fit into the factory air intake box. The Pro 5R is constructed of five layers of progressively finer mesh cotton gauze media providing maximum airflow for best performance results. Washable and reusable for multiple cleaning cycles, the tall open evenly space pleats provide excellent dust holding capacity for longer service cycle between cleanings. Integrated urethane bump seal insures tight, no leak seal over the life of the filter.