Hifonics ZXi4404. Audio output channels: 4.0, Total Harmonic Distortion (THD): 0.015 %, Signal-to-Noise Ratio (SNR): 91 dB. Connectivity technology: Wired. Power requirements: 12 V DC, Dimensions (WxDxH): 380 x 260 x 60 mm, Output power: 4 x 100/200W