C2G Plenum-Rated 45 Watt Stereo Mixer/Amplifier. Impedance: 4 Ω, Frequency range: 20 - 20000 Hz. Power requirements: 100 - 240 VAC / 18 V @ 3.5 A, Dimensions (WxDxH): 5.45 x 4.05 x 1.65" (138.4 x 102.9 x 41.9 mm), Output power: 45 W. Weight (imperial): 2.75 lbs