ReX 2 with a standard power supply unit operates off 110-240 VAC mains.
To connect ReX 2 to 12 V circuits, use 12V PSU.
12V PSU is required to connect the range extender to the power system of a car, trailer, yacht, or an external battery/power supply.
To connect ReX 2 to 6 V circuits, use 6V PSU.
6V PSU is required to allow the range extender to run on an external battery for years — without being connected to the facility’s electric power system — and be ready to protect run-down or empty premises as well as buildings under construction against burglars, vandals, or unauthorized occupants.
You can calculate the run time of ReX 2 from an external battery using a calculator.