Opti-fiber media with low pressure drop characteristics|75% minimum average efficiency 1 to 3 microns|Replacement media 6FM2025 (GFI #4551 - MERV 11) or 5FM2025 (GFI #4501 - MERV 10), (change every 6 months)|22 gauge, galvanized cabinet with metal door|10 or 12 x 26-1/2 in adjustable inlet duct opening|Furnace opening adjusts from 19 or 22-1/2 x 26 1/2 in|Solid cabinet|Made to fit 1.3 or 3.5 ton electric air handlers or gas furnaces|Removes dust, dust mites, pet dander, pollen and more, airborne particulates as small as 0.01 microns|Space saving design for vertical installations, keeps furnace off floor, allowing a clean, professional installation|Two pull-out doors allow easy access for filter changes|Eliminates the possibility of dust, pet hair, insects, rodents, water or sewer backup from entering the furnace|Hydrophobic (resists moisture) filter media|New filter platforms by GeneralAire® offer the most well-built, sleek designed and easiest to use galvanized sheet metal filter housings on the market|Allows furnace to work at maximum efficiency and extends life of furnace by providing even air flow distribution across bottom|Especially ideal for High Efficiency Furnaces, where side returns require more installation time and are inefficient compared to a bottom return|Allows filter to work at maximum efficiency by eliminating need for transitions deflectors or turning vanes, thereby saving installation time and costs|Made to fit 1 to 3 ton or 3.5 ton electric air handlers or gas furnaces|Ideal for homes with allergy, asthma or respiratory sufferers, smokers, pets and mustiness|Helps protect and prolong the operating efficiency of the heating and cooling system

ANSI/ASHRAE 52.2-1999