... time keep working in 8-12 hourse Function Mp3, FM radio, Amplifier, loudspeaker, microphone, reverberation Digital mini professional portable speaker with lithium ... box.We have other style that have function such as FM Radio, USB/TF/MMC input ,music reverb and telecontrol etc ... more function, I will recommend you as your request . OEM wireless microphone with USB for teachig, meeting, restaurant