SURGE PROTECTION DEVICE CLASS I + II SPD for use in AC SystemCLASS I + II SPD for 3- Phase use in AC SystemCLASS II SPD for use in AC SystemCLASS II SPD for 3-Phase use in AC SystemCLASS III SPD, for Low Power Supply System 12V, 24V, 48V, 60V, 120V, 230 V