Healthier & Happier Eco-safe Air Filters FPR9, 20 x 20 x 1, reusable frame washable refill sheet, environmental friendly, Keep indoor air clean! Live a healthier life! Environmental friendly: 100% recyclable as paper & plastic, No Waste! Saves money: the plastic frame lasts 3-5 years, inserts is washable and reusable, can last whole year Reduce Allergy: Can filter out all unwanted Particles in the air which might cause Allergy. User friendly: Easy to install and exchange inserts. Two Way Technology  Impossible to install wrong. Two types of Refill Eco-safe Air Filter Sheets: (1) High Filtration Sheet (white color) efficiency: captures microscopic particles like smoke, smog and large allergens like mold spores and pollen from the air passing through the filter. FPR 10 rate (Ref: Home Depots); (2) High Air-flow Filter Sheet (light green color) is FPR 9 rate, effective against these common household contaminants. Out performs disposable air filters.