Our KRE-4000 series relay switching units are mainly used for the automation of EMC tests. They control the switching between the individual power amplifiers to enable a broadband measurement according to test standard without manual switching. The selection of the relays is done individually according to the customer’s requirements (frequency range up to 50 GHz possible). However, the application of the switch panels from MTS Systemtechnik is not limited to this relatively simple case. By means of examples the flexible application of this powerful device concept will be shown.