Lennox Corporation X0581 Media Filter MERV 11 16X25X3 Use in Lennox Healthy Climate BMAC-12C Air Cleaner MERV 11 Efficiency to capture particles as small as 0.3 microns Actual Size: 15-7/8" x 24-1/4" x 3" Replace every 6 months in normal use Genuine Lennox OEM Filter