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 BETA ENDURO 125RR 13-18 250RR 13-19 300RR 13-19 350RR13-19 390RR 13-19 400RR 13-19 430RR 15-19 480RR 15-19 498RR 13-19 500RR 15-19 525RR 13-19 X-TRAINER 250 18-22 X-TRAINER 300 13-22