Classic 400 Series Particle FilterClassic 400 Series · US · OEMVerified for US models only.Official manufacturer / OEMBlueairClassic 400 Series Particle Filter↗Aftermarket listingsFilter-MonsterBlueair Classic 400 Series HEPA replacement↗Aftermarket compatibility is stated by the seller or maker and is separate from Filter Fit evidence.Full part details →Open manufacturer source ↗Evidence A · BlueairView evidence ↗