728UDFM Portable wireless amplifier 1.Mic:wireless/wire mic 2.Support:FM radio,USB,SD card 3.Battery:build-in rechargeable 728UDFM ... Input Signal:Wire/wireless Mic, Audio(USB,SD Card), FM radio. Frequency Range: 175MHz-276MHz(Wireless Mic) Sensitivity:10dBS/N:>60dBOscillating: ... , tour guide, assembly,speech,etc.Our 728 series PA amplifier can let your voice get louder and sounds more pretty ...