The Leader LT4670-SER11 Redundant Power Supply Unit Hardware Option is a factory-installed option for the LT4670 Sync Generators. This option installs a second power supply unit onto the instrument that is hot-swappable along with the fans. In the event of a power unit failure, an alarm is displayed on the front panel of the instrument and an alarm can also be output via SNMP. Replacement of a power supply unit without needing to turn the instrument off prior to removal is possible with two units installed.