XCSOURCE TDA7492 Amplifier Board 2x50W Class D Digital Power + Cooler AMP Board TE398 Small Super Powerful Voice amplifier/speaker. Rechargeable lithium batteries that last 10-15 hours of continuous use. Sound covers over 3,500 square meters. Can also be used MP3 speaker. The amp has a microphone input and a MP3 input. The use of high-speed SMT placement machine, excess temperature reflow, the performance is very stable.