BLUEAIR GENUINE FILTER: For Blue Pure 411i Max (B0BN2LH4RK) and 411a Max (B0BN2HZX1C) air purifiers; Blueair genuine Blue Pure F4MAX Replacement filter for 411 Max Series is designed for optimal performance; Not compatible with 411, 411 plus and 411 Auto LET’S CLEAR THE AIR FASTER: HEPASilent dual filtration technology delivers more clean air faster and uses less noise and energy than HEPA filtration alone LET’S CLEAR THE AIR BETTER: Removes at least 99.97% of tiny airborne particles like viruses and smoke down to 0.1 microns, and captures pet dander, pollen, mold allergen and dust; carbon filter traps light household odors from smoking, pets and cooking** MOST AWARDED AIR PURIFIER BRAND IN THE US: Independently tested for performance, Zero Ozone; AHAM Verifide for Performance (CADR); Quiet Mark Certified; Ozone Safety Standards Certified by CARB; Zero Ozone Verified (<5 ppb) by Intertek Sustainability