USB FM radio waistband amplifier with reverberation of sound with headset microphone used ... 20 hoursWith digital display, also show bettery usageOuput power: 12 W, clear and nice loud voice, good penetration. Technique Data:Output ... working time Keep working in 7-8 hours Function Mp3, FM radio, Amplifier, loudspeaker, microphone, reverberationColor ChoiceBlack,Red, BlueWeight 225g ( including battery ...