How to identify the quality of car air filters?
but PP depends on the thickness of the casing, the hardness of the paper, PU to see the production of fine degree of apron, the hardness of the pape
environmental protection is more simple, see the thickness, hardness, surface is neat because I! Do the auto filter, so I know! I opened a shop: Huayi auto Wangwang ID:qhhuanglei1129
Your answer is too layman, filter is divided into PP PU and environmental protection is not false
