Nominal Size: 20x25x4 Actual Size 19.375x24.375x3.625 Actual Size: 19.375x24.375x3.625 compatible with TopTech TT-FM-2025 TTFM2025, TT-FM-2025QB, Fits TechPure TT-MAC-2522 TT-MAC-2025 TT-MAC-2129 Air Cleaners (no assembly required) Case of 3 Filters MERV 11 Made in the USA Filters should be changed every 3 to 6 months 20x25x4 air filters, furnace filters, air conditioner filters and HVAC filters. Replacement AC Furnace filters from Atomic Filters are high quality AC filters. The MERV 11 filter media is electrostatically charged and constructed with 100% high performance mechanical synthetic media, moisture-resistant. These HVAC filters should be changed every 3 to 6 months for optimum performance. Atomic offers our filter in 1” and 2” and 4" thicknesses to fit just about any home application. Compatible with Toptech TT-FM-2025 and TT-FM-2025QB Fits TechPure TT-MAC-2522 TT-MAC-2025 Air Cleaners (no assembly required)