AmazingAir 3500 UltraHEPA Replacement FilterAmazingAir UltraHEPA filters last for one year (under normal use) and are designed to capture ultra fine PM 2. 5 particles from the air. That is 100 times smaller than regular HEPA filters. Time to Replace a Filter? No guesswork needed! AmazingAirs smart display will let you know exactly when its time for a filter change. A filter icon will light up on the control panel, so youll always stay on top of maintenance. Simply replace the used filter with a