18x20x1 merv 13 pleated ac furnace air filters. 6 pack actual size: 17-1/2 x 19-1/2 x 7/8 | nominal size: 18x20x1 filtration rating: merv 13. comparable to mpr rating 1900 to 2200, or fpr 10 rating. effectively captures and blocks small-particles such as virus carriers, bacteria, allergens, smog, smoke, lint, dust, pet dander and pollen. made in the usa recommended to replace at least every 90 days.
