Sony CDX-GS500R Single DIN Car Stereo With Pandora Control Power Ad Hoc: CEA2006 Standard Power: 17 Watts RMS per channel into 4 Ohms Speaker Impedance: 4-8 Ohms Max power output: 52 watts x 4 at 4 ohms Preout Voltage: 5 volt Preout Impedance: 220 ohms