... ” PP-R aluminum-plastic composite pipe consists 5 layers, in the middle layer is aluminum, outer layer is PP-R, inner layer is PE or PP-R, between ... no fouling and long service life etc.PP-R Aluminum-plastic composite pipe is widely used in pipe systems such as heater, solar energy, ... has the advantages of both the metal and plastic pipes.specification:20~75mm PP-R Aluminum plastic composite pipe