Aprilaire 501 Replacement Filter

Patented, breakthrough technology provides air cleaning performance never before possible. It's 94% efficient at removing disease-causing bacteria as small as 0.35 micron. The Aprilaire 501 even traps virus-sized particles with unsurpassed efficiency of 80%. Over 99% efficient on pollen and spores. Air Cleaner media lasts one to two years. Protects heating and cooling equipment. No monthly cleaning of collector plates. An excellent choice for healthy indoor air.