The dual voltage option is available for the 115v 5000 and 9000 series units only. Depending on the application, these kits are constructed of a typical FCF kit plus an ignition protected Xantrex IP1012 series power inverter or a non ignition protected Xantrex HF1800 series power inverter as well as a cable kit to integrate the inverter into the system (Two sizes available). These components are sold separately, please contact Webasto for further information.