Two source, 6.5inch, amplified drop ceiling speaker with Bluetooth on a 2X2 full grill with backcan delivers up to 40W power directly to the speaker. Each powered speaker (2X2FG-BT2S61) can drive three additional speakers (2X2FGIC6NA). One line can drive up to 10 self-amplified speakers. Lower noise feature and protection from shorts and overheating. 15VDC Level 5 power supply included and optional volume control available.