... used for tour guide,teaching teaching portable wireless amplifier Item: GS-102 High lights:Multifunction all in one with ... supply: rechargeable with high capacity Lion battery, keep working with 20 hoursWith digital display, also show bettery usageOuput ... timeKeep working in 7-8 hoursFunctionMp3, FM radio, Amplifier, loudspeaker, microphone, reverberationColor ChoiceBlack,Red, BlueWeight225g ( ...