External
From think.pedia
External Differents are those that function off of an external power source. These individual's abilities, require a specific source of energy in order to function. Some External Differents are able to live almost entirely off of their external power source. They require nothing else besides some water and vitamins. Others have normal caloric and nutritional requirements, but need access to their external power source in order for their abilities to function.
The external power sources used by these Differents vary greatly. The most common externally powered Differents require solar energy, heat, sound waves, or physical force.
