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. APPLICATION Yamaha YZ 125 (1997 2025) YZ 125X (2020 2025) YZ 250 (1997 2025) YZ 250F (2001 2013) YZ 250X (2016 2025) YZ 400F (1998 1999) YZ 426F (2000 2002) YZ 450F (2003 2009)"> "> 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. APPLICATION Yamaha YZ 125 (1997 2025) YZ 125X (2020 2025) YZ 250 (1997 2025) YZ 250F (2001 2013) YZ 250X (2016 2025) YZ 400F (1998 1999) YZ 426F (2000 2002) YZ 450F (2003 2009)"> "> 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. APPLICATION Yamaha YZ 125 (1997 2025) YZ 125X (2020 2025) YZ 250 (1997 2025) YZ 250F (2001 2013) YZ 250X (2016 2025) YZ 400F (1998 1999) YZ 426F (2000 2002) YZ 450F (2003 2009)">