Filtrete Air Cleaning Filter, Replacement Filter For The FAP01-RS, Small Room Air Purifier & FAP02-RS, Medium Room Air Purifier, Advanced Filtrete Filtration Technology Effectivly Captures 99.9% Of Airborne Particles & Allergens, Filter Change Indicator Senses The Particle Accumulation On The Filter, Taking The Guesswork Out Of Filter Change, No Ozone Generation. .