Two Source, 6.5", Amplified Drop Ceiling Speaker on a 2X2 full grill, plenum box and backcan delivers up to 40 watts power directly to the speaker. Each powered speaker (2X2PB-R2S64) 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. 15 Volt DC Level 5 power supply included with optional Volume Control. Available also in Bluetooth models.