The patented Semper concept enhances the safety and reliability of the well-known and proven gas discharge tube (GDT) protector principle impressively. It eliminates the risk of gas discharge tube "hold on" due to DC line powering or high powered RF signals, which will render the system inoperable and can destroy the discharge tube. HUBER+SUHNER offers a unique concept of self-extinguishing GDT protectors. The unique and patented Semper solution is realised as a simple unit which enables the use of the comprehensive range of HUBER+SUHNER GDT protectors with a replaceable GDT. An easy retrofit of existing GDT protectors is possible or available as complete Semper protectors in a variety of configurations. Whereas many applications generally benefit from the enhanced safety and reliability that the Semper concept offers, applications using DC line power for remote signal amplification and processing and those using high RF power will find self-extinguishing lightning EMP protectors of specific interest.