Specifications: This is a 4-channel amplifier for your reference: US-4028P 4-channel Power Amplifier Operating Voltage: DC 14.4V RMS Power at 4 ohms:70w*4ch T.H.D.:RMS Power at 2 ohms:140w*4ch T.H.D.:Maxpower at 4 ohms: 270w*4ch Bridged RMS Power at 4 ohms: 240w*2ch T.H.D.:Frequency Response:20Hz-35KHz Input Level: 200mv-4.5v S/N Ratio: >=95db