20x25x4 merv 8 ac furnace 4" inch air filters | 4 pack (actual depth: 3-3/4") exact size: 19-1/2 x 24-1/2 x 3-3/4 | nominal size: 20x25x4 | effectively captures and blocks small-particles such as dust, smog, lint, pet dander, dust mites, pollen and other small air particles. filter rating: merv 80 | fpr 5-6 | mpr 600. achieves merv 8 pressure drop and air flow.
