Tier1 Replacement for Lennox 16x28x6 Merv 11 X5425 Air Filter 2 Pack Upgraded media rated at MERV 11 to capture 90% of particles, 1-3 microns in size Replacement for: Lennox X1444, X4559 and X5425 98% efficient filter media that captures small dust particles before they can collect on your coils This product is listed and rated by Underwriters Laboratories as U.L. Class 2