Arlen Ness Stage I Standard Replacement Air Filter 18-098 99-up FXST, 02-07 FLT, 97-07 FXD, 08-up FLT Each pre-oiled filter is hand poured in the USA and uses 4 layers of surgical grade cotton for the best performance and filtration available. Big Sucker filters accept OEM cover or allow the use of Ness Stage I custom cover. Put the original Big Sucker filter on your HD Screaming Eagle air cleaner kit for increased airflow and performance. Washable & Re-usable, filter tune up kits are available separately.