The GEMÜ Code 5M diaphragm is made in two parts and consists of a PTFE shield and a peroxide-linked EPDM backing. An FKM back is also available for strongly diffusing media (GEMÜ Code 5F). The PTFE used is a chemically modified second generation PTFE, the so-called PTFE TFMTM. This material offers a high level of chemical resistance and also shows significantly less wear when exposed to steam. 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.