The production of medium-voltage arresters at TRIDELTA has a long tradition, since the first medium-voltage arresters have been produced in 1962. The housing of these valve arresters has generally been made of porcelain. Since 1996, the medium-voltage arresters have only been manufactured with a light and cost-effective silicone housing. For arresters without spark gaps we use high-quality ZnO varistors. The arresters have successfully stood the 5000-hour test. We supply arresters for two different nominal discharge currents: *nominal discharge current of 5 kA -------> leaflet 1382 *nominal discharge current of 10 kA ------> leaflet 1384