3PE mainly meaning every pipeline has three PE layer：The first layer is FBE（FBE＞80um），The second layer is AD（170～250um）,The third layer is PE(1.8～3.7mm）。Three kinds of material  mixed  together one organic whole, become solid combination with steel pipe forming excellent anti-corrosion layer.
    2PE mainly say every pipeline has two layer of PE:The first layer is AD,the second is PE,two material mixed together one organic whole,thickness of every layer is same as 3PE.3PE produce process as follows: