... filter, primary filter, medium filter, pocket filter, heap filter, dust filter, powder filter and so on 3004WB mini pleated air filter1) high efficiency,low resistance 2) easy installation ... 3) light weight, thin, only 50 mm in thicknes 4) low operating cost 5) each filter is ... 99.995% efficiency 7) type: hp mini-pleat hepa filter 8) frame: aluminum 9) media: glass fiber paper ...