Honeywell CF112D1620/U MicroDefense MERV 12 Superior Household 1 Inch Air Filter, 4-Pack Outperforms competing filters including 3 month electrostatic pleated & washable 1 Inch filters that lose performance upon loading with dust MicroDefense carry a rating higher than any competing model & capture small & large particles including smoke, smog & particles that carry viruses. Easy-flow energy efficiency provides an additional layer of defense against harmfule airborne particles that no filter can match. Maximizes indoor air quality with existing furnace equipment Lasts up to 90 days so buy a years supply of 1 Inch Replacement Filters