ktv amplifier 1.with USB/MP3, SD card &recording functions ... 3.ktv user,teaching ktv amplifierThis product is digital portable amplifier with USB port and SD card reader,use Lithium ... it&waistband, easy to carry, Small in size, show a clear voice, strong volume, the use of simple and ... time8~14 hours Standard Configuration:1 pc main machine(Amplifier) 1 pc Headset Microphone(4 different style for choose ...