deso pipe is a composite pipe of five layers. the inside layer is made of pe, laser butt-welded by an aluminum layer, then covered by the outside pe layer. between the aluminum layers are the bonding adhesive layers. all layers are extruded in one step. the pe layer can be made form cross-linked polyethylene (pex) or high density polyethylene (hdpe). deso pipe uses special pe which is hygienic, toxic-free and smooth. the middle aluminum layer is 100% gas/oxygen tight. such structure provides deso pipe the advantages of both metal and plastic while avoiding their weaknesses