Arlen Ness AN-81-010 90 Degree Monster Sucker Air Cleaner Kit Black for Sportster 91-21Description for Arlen Ness Monster Sucker Black Air Cleaner Kit 81 010 Monster Sucker kit features our patented Big Sucker "hidden breather"? technology and more filter surface area for maximum performance Hidden breathers are o ringed at the heads and exist out the mouth of the injector carb to provide efficient engine breathing, eliminating the need for any external hoses or hardware Filter features a built in inverted top to pull in air not only