Kimdrox 15w+15w Dual-channel Power Amp 12 Volt Small Digital Audio Motorcycle Stereo Amplifier Ampli Kit Power source: DC 9-18V, Recommend 12V 2A Chip: TDA7297 Dual-Channel Amplifier Chip Output Impedance:4-8 ohms efficiency: up to 90% please follow the picture to connect the Power Supply and Speaker.