Description Product Reviews Porta Systems gas tube modules are dependable plug-in devices that guard sensitive telecommunications systems from dangerous voltage surges. The gas tube utilizes a three-element sign. This prevents destructive line-to-line over voltages, protecting PBXs and key systems in a way that conventional two-element gas tubes cannot. The modules include heat activated fail-safe mechanism that provides additional protection against power crosses. Test points allow easy test access to the outside plant. Features & Benefits UL 497 Listed for Primary protection Balanced three-electrode design Secondary air gap Detent position facilitates testing Test point contacts Fail-safe mechanism Heat Coil (on selected models) Prevents costly damage to circuitry Extends equipment life Protects personnel 0 Reviews Hide Reviews Product Reviews