The GEMÜ Code 54 membrane consists of a PTFE shield and a peroxide-linked EPDM backing that are firmly connected to one another (fully laminated). An FKM back is also available for strongly diffusing media (GEMÜ Code 56). The PTFE used is a chemically modified second generation PTFE, the so-called PTFE TFM ™. The membrane combines all the advantages of the material PTFE and the flexibility of an elastomer membrane. In order to optimize the overall system, both the PTFE shield and the membrane back are compounded for GEMÜ and manufactured within the GEMÜ Group.