Combined terminal block surge protection, tested in category D, C, B (EN 61643), suitable for twisted pair cables for signal transmission in hazardous environments (ATEX/IECEx approved). For use at limits from LPZ 0 for protection against flashover up to LPZ 3 to protect sensitive electronic equipment. Available for nominal voltages of 15 and 30 V, optionally with LED, for earthed and earth-insulated systems.