Volants high performance , 5 layer oiled cotton gauze air filters are made of the highest quality textiles, pleated between a top and bottom aluminum screen. Each filter comes pre-oiled and ready for use. This design will allow the highest air flow rate possible and a very long filter life and maintenance intervals (up to 40K miles depending on driving conditions). Use Volants two stage cleaning kit to thoroughly clean and re-oil the filter. We recommend cleaning the filter only when necessary. Inspect the filter every 12,00-15,000 miles to ensure peak operation.