Engineered Polymer Technologies (EPT) manufactures Cured In Place Pipe (CIPP) Calibration Tubes and Membranes that are available in thermoplastic urethane (TPU) or polyvinyl chloride (PVC) designs providing you with the perfect product for your particular CIPP process. XTRM Ply Calibration Tubes and Membranes are a composite of our proprietary TPU, or PVC, which are reinforced with a nylon woven fabric that provides consistent pressure and support during the CIPP curing process.. These products provide a dimensionally stable product that performs at temperatures from –30° F to 300° F.