True Blue Cold Air Return Filter Pad, 10x30;

The True Blue Cold Air Return Filter Pad has electrostatically charged filter material that captures sub-micron airborne allergens like dust, dirt, pollen, pet dander and smoke. The electrostatic filter material attracts very small particles much the same way magnets attract metal. It is designed to fit your cold air return vent and filter dust and dirt particles before entering the furnace or air conditioning duct system. Cut-To-Fit Design, attaches easily to the back of your cold air return vent. It Lasts up to 30 days and measures 10-inches by 30-inches.