TN 398279 Cylindrical Inner Safety Engine Air Filter for Tennant Sweepers and Sweeper/Scrubbers. Inner cylindrical air filter for many popular Tennant sweepers and sweeper scrubbers including 550, 1550, 6600, 6650, 7400, 8410, M20, M30, T20, and S30. This is the inner "safety" air filter which fits inside of the TN 369746 outer air filter element. TN 398279 has pleated filter element surrounded by metal mesh with 6 spline molded ends. Commonly blue and black in color. Priced Each. Replaces Tennant 398279. Our Part Number TN 398279