Primary filter: the basic filter necessary for every purification needs, mainly filtering hair, fiber, large particles, dander, etc. for indoor air.

Medium-efficiency filter: can filter 0.5um ~ 50um particles, which can extend the service life of the high-efficiency filter.

High efficiency filter (HEPA): For particles with particle size of 0.3um, the filteration efficiency is about DOP 99.97% or more.