Waistband portable teaching microphone headset,usb,tf card slot, mp3 ,fm radio,microphone, ... .4 V/ 2000 mA Battery working time Keep working in 7-8 hours Function Mp3, FM radio, Amplifier, Line-in, loudspeaker ... .5kg ( including battery )Size128*50*85mmApplication:Used for Yoga, Gymnastics,Teaching, Conference,Acoustic Instruments,Camping and other outdoor EntertainmentAccessories:Headset Microphone ...