... USB card waistband amplifier Lower pirce! Portable Microphone for teachers,meeting,restaurant,etc Multifunction all in one with Entertainment,Microphone ... : 108*90*38mm Mic sensibility: -53±3dB Recharge Time 4-6 hours Battery working time keep working in 8-12 ... stand-by time and perfect for outdoor activities, tour guide, teachers, conference, outdoor lecture, parade, assembly etc. This mini portable ...