The OWI AMP-R2SIC54SVC Amplified Drop Ceiling Four Speaker Package delivers up to 40 watts power directly to the speaker. Each powered speaker can drive three additional speakers. One line can drive up to 10 self-amplified speakers. It features lower noise and protection from shorts and overheating. The 15 Volt DC Level 5 power supply included. Four speaker combination package consists of the following: one each 5.25" amplified speaker, three each IC5 In-ceiling Speaker, four each Backcan enclosure, four each 5TB tile bridge and one each Stereo/Mono Volume Control.