... Portable wireless amplifierSpecifications:Power:70W Maximum Output Power:60W+60W/4Ω @ 1% THD, 1KHz (channel L/R) Frequency Responses: -3dB, 0dB ... Distortion: 1% @ 1KHz, output 40W (channel L/R) Speaker: 5*4 woofer Built in receiver:UHF 700-820MHz, 300 channels Power ... promotion, tour guide, assembly,speech,etc.Our Teaching series PA amplifier can let your voice get louder and sounds more pretty ...