Bionaire ''AER1'' 99.99% True Hepa Replacement Filter is ideal for allergy sufferers. This replacement filter features enhanced mould capturing technology and, as a true HEPA filter, is able to purify up to 99.99% of the air that passes through the filter. It is a wise choice to reduce allergens and pollutants (pollen, dust, mite residue, mold, pet dander and smoke). This filter is compatible with all ''AER1'' ready air purifiers. It is recommended to replace your filter every 8-12 months for maximum efficiency.