With five layers of progressively finer oiled cotton gauze and 2-layers of finer porosity synthetic non-woven media for highest filtration efficiency for extreme dust environments (US PAT 06811588). 100% polyurethane top and base, the aFe Pro-GUARD 7 “oiled” high performance filter provides excellent airflow for maximum horsepower and torque. Washable and reusable for multiple cleanings. The tall, open, evenly spaced pleats provide excellent dust holding capacity for longer service cycle between cleanings. Pliable polyurethane construction insures tight, no leak seal over the life of the filter.