Surge protection for use in measurement, control and regulation technology. Basic, medium and fine protection. Two-stage protection circuit with high lightning current discharge capacity. High transmission frequency of 100 MHz. Universal for all bus systems (e.g. Profibus). With easy-to-install, screwless connection terminals. In a space-saving 17.5 mm grid dimension. Application: Universal use on 35 mm top-hat rails in commercially available distribution boxes.