SainSmart TDA7492P 2 x 50 Watt Dual Channel Amplifier Wireless Digital Bluetooth 4.0 Audio Receiver Amplifier Board 50W + 50W Output Power: Add Pre-5532 output foot powered 25V, 6 impedance output 2x50W Power: 2.1 interface 8-25V DC power supply Output Impedance: 8 (Best), 4/6/8/16 impedance can drive speakers Chip: TDA7492P,The sound quality is very good, big power.