The all new Accumulair Diamond with it's MERV 13 rating is the highest efficiency Accumulair filter on the market! Electrostatically charged filter media captures airborne allergens smaller than 1 micron! Over 30-times more efficient at capturing micro particles than ordinary fiberglass filters. Lasts UP TO 3 months! The Accumulair Diamond (MERV 13) has the same airflow as the Accumulair Platinum (MERV 11)! Proudly made in USA.