Surge protective devices (SPD) to protect sensitive equipment from the harmful effects of lightning strikes and other power line disturbances. Transient voltage surge suppression products and components including AC power, DC power, RF coaxial, Analog Signals, Discrete Signals, Ethernet, POE, other data line, and component-level gas discharge tube (GDT) surge arrestors. When you need to protect something that conducts, think Citel Surge Protective Devices.