It is a 3-point overvoltage protectors designed for protecting against metallic (differential mode) and simultaneous longitudinal (common mode) surges. Each terminal pair has the same voltage limiting values and surge current capability. This terminal pair surge capability ensures that the protector can meet the simultaneous longitudinal surge requirement which is typically twice the metallic surge requirement.Each terminal pair has a symmetrical voltage-triggered thyristor characteristic. Overvoltages are initially clipped by breakdown clamping until the voltage rises to the breakover level, which causes the device to crowbar into a low-voltage on state. This low-voltage on state causes the current resulting from the overvoltage to be safely diverted through the device.