TN 58121 Safety Inner Engine Air Filter for Tennant Sweepers and Sweeper/Scrubbers. A cylindrical type drop-in inner air filter. Commonly used on heavy-duty engine filter optioned machines inside of the primary engine air filter, TN 58120. Fits diesel, LPG and gasoline powered Tennant sweepers and sweeper/scrubbers such as the popular Tennant 355, 355D, 385, 385D, 385DLH, 6500, 6500D, 6550, 6550D, 6600 (Diesel Only), 6650D, 7400, 7400D, 8200 (Gas/LPG), 8200D, 8210 (Gas/LPG), 8210D, 8400, 8400D, 8410, and 8410D. Please check your parts book for proper application since models equipped with Gas/LPG engines may require a different engine air filter. Works in conjunction, on some models, with the outer filter, TN 58120. One filter required per unit. Priced Each. Replaces Tennant 58121. Our Part Number TN 58121