Price history on Walmart.com for
AAF Flanders (4 Filters) 14 x 20 x 1 Nested Glass MERV 1 Air Filter
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This is a standard grade furnace filter of the same type that has been protecting furnaces and central air conditioners around the world for over 50 years. The filtering medium is continuous filament spun glass. For peak equipment protection and energy efficiency these filters should be changed monthly.
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