filtering media:chemical fiber,efficiency grade:G3-G4,cheap.
aluminum frame, washable, replaceable filtering media.
The filtering efficiency has the following two kinds--G3 and G4 and the corresponding weightmethod efficiency is 80% -90% as well as the efficiency of colorimetry is 40%.The filters with this efficiency is not only usually used in the primary filtefor air-condition and ventilation systems but also used in simple air-condition and ventilation systems that only needs the one-stage filtering.