25x20x1 MERV 2 Non Pleated Air Filter Replacement Filters (Actual Size 24.75 x 19.75) - 3 Pack Compatible With Duct 6in + Product Details Size -

+ Product Details Size - 40"w X 20"h is the size for the duct opening measurement only

Its smooth

actual front end outer dimensions are approximately 20 5/8" width X 26 5/8" height

designed to prevent corrosion

+ Product Details Size – 24"w X 34"h is the size for the duct opening measurement only

25x20x1 MERV 2 Non Pleated Air Filter Replacement Filters (Actual Size 24.75 x 19.75) - 3 Pack Compatible With Duct 6in + Product Details Size -+ Product Details 25" x 20" x 1" replacement air filters for your furnace, air conditioner, heat pump, or HVAC system (actual size: 24. 75" x 19. 75") A unique combination of cotton & synthetic fibers gives you the most filtration and the least air resistance equals great air & easy airflow for your system. The non pleated design provides low airflow resistance while still effectively capturing dirt and particles such as standing dust, spray paint