Premium quality replacement pre filter and particle carbon filters kit compatible with Blueair Air Purifiers Removes harmful household odours, chemicals, and gases, as well as 99.97% of airborne particles, including pollen, dust, germs & much much more… Fits models: Blue 3210, Blue Pure 411, Blue Pure 411+, Blue Pure 411 Auto, Joy S Kit includes: 1 x Blue fabric pre-filter - catches larger particles to extend the life of the filter. (Can be gently vacuumed or put in washing machine) -- 1 x Particle carbon HEPA filter - removes allergens, dirt, household odours and traps particles for good. To maintain optimum performance, we recommend changing your filter every 3 months (heavy use), 6 months (normal use), 9 months (light use). This product is designed to be compatible with the specified brand(s) and is not the original part. The name, model names and any part numbers of the original manufacturer(s) have been used for reference purposes only and are in no way associated with the original parts or manufacturer.