Filters are pre-oiled with Twin Air BIO foam filter oil using our state-of-the-art filter oiling machines to provide the ultimate consistency in pore coverage The same factory treatment that race teams and OEMs receive is now available for all Twin Air users Same industry-leading Twin Air Filter you are used to, now pre-oiled for your convenience Come in a new, resealable bag for added convenience. AIR FILTER PRE-OILED YAMAHA YZ450F