18x20x1 Merv 13 Pleated AC Furnace Air Filters by Glasfloss Industries. 6 Pack

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.