... V-3 Mini size big power waistband teaching tour guide speaker with Reverb/Echo Features*Mini size,easy to take*18W ... Connect computer with USB data link, used as speaker*Built-in 3" high power speaker, high sensitivity microphone*Built MCU Intelligent recharging ... & waist band Specifications*Max output: 18W *Frequency response: 80Hz-12kHz*Speaker: 3" 4Ω*Working voltage:7.4V*Recharging time:Approx 6hrs ...