... for consumers. The built-in 16 user selectable channels wireless microphone receiver module, which can avoid interfering with the ... use for 2 to 8 hours, use lithium battery rechargeableElectrical charger use (90 -264 volt AC)Tone control, main ... ,MP3 control,microphone control,echoes control16 channel frequency UHF wireless microphone with volume control.Using shattered proof synthetic material ...