Zinc alloy metal shell Patented technology Built-in rechargeable lithium battery A kind of special speaker, without sound device inside It depends on a high-technical crystal to shake any hard surface, like wood, glass, wall, stone and more and make hard surface send out the music Patented technology, zinc alloy metal material shell, small, simple, durable, portable and fashionable design, built in rechargeable lithium battery, usb powered Parameters: Power supply: 5 to 6v dc Power consumption: 3w (maximum) Frequency response: 100hz to 20khz Dimensions (l x w x h): 81 x 80 x 35mm Weight: 360g Package: each in a color gift box Package included: host 1 piece, usb special cable 1 piece, product specification 1 piece, pure metal crust. Color gift box