This filter features three layers of oil-free synthetic media and requires no oil during maintenance to provide maximum convenience. Its progressive layering provides great filtration efficiency and dust holding capacity. This media is best suited for street use. Pro DRY S filters are easily recharged with aFe's POWER CLEANER. aFe POWER performance air filters use a rounded, evenly spaced pleat design which allows for more usable filter surface area, providing increased flow and greater dust holding capacity.