The MYS5-440/20-4P and MYS5-440/20-4P (NS) are modular surge protective devices (SPDs) designed for TN-S systems using a "4+0" circuit configuration. Both models are classified as Type 2 according to EN 61643-11 and Class II according to IEC 61643-11, making them suitable for installation at the distribution board level to protect electrical installations against transient overvoltages caused by switching operations or indirect lightning strikes. Both devices feature an AC