The efficiency of air filter media the can be achieved from G1 to F9,that is, the primary air filter media and medium efficiency air filter media, if high efficiency air filter media is needed, the thickness and the density will be increased accordingly.
The Thickness and efficiency are related as follows，
30mm with fine synthetic fiber material,F6
5-8mm with fine synthetic fiber material, F5-F9
Normally, what we are talking about is synthetic fiber air filter media, the thickness of the material will be 3mm, 5mm, 8mm, 10mm, 15mm, 20mm, 22mm, 25mm, 30mm, etc and 30mm is the maximum thickness.
Once the thickness of the air filter media is more than 30mm, the resistance will exceed the force of the fan,will influence the effect of air filter media.