Original Dual-Stage Air Filter completely submerged in Filter Oil. The filter is then massaged to ensure all pores are evenly coated with oil, it is then placed in a temperature-controlled room to allow the oil to completely cure. All you have to do is open the bag and install. AIRFILTER PRE-OILED MONTESA 315R 97-04 4RT 250-260 05-24 4RT 300-301 16-24