Lennox Y4593 - 1st Generation to 2nd Generation Conversion Kit: Healthy Climate PCO-20C MERV 11 w/ Insert 21x26x4

Rest assured and breathe easy with the only indoor air quality system that safely removes and destroys odors and chemical vapors. It also reduces concentrations of pollutants through a process called photocatalytic oxidation (PCO) that combines three of nature's most powerful air purifiers; ultraviolet light, titanium dioxide catalyst and hydroxyl radicals