A:Answer It supports 4 outlets that are individually controlled (there is a knob on the top to choose if you want all four to blink the same or blink different to the music.) If you have more than 4 strings of lights, then you can plug in multiple into each outlet (up to the recommended 400 wattage per plug). There does not seem to be a way to synchronize multiple base units together, so that they would play the same song. If you had extra receivers they would still use the same 4 channels and the wattage per plug would be reduced -- "For example, if you buy two extra receivers (total of 6 now), each receiver can only have 280W so that the 1680W max will not be exceeded." (http://support.mrchristmas.com/)