Metal speaker/Heavy/Nice sound Function: Speaker/Handfree/FM radio/TF Card Material: Metal+ABS Logo: Laser engrave on speaker top net/silk screen on metal body Packing: Blue gift box with window/White gift box optionnal Bluetooth version：V2.1+EDR Bluetooth transmission power:   CLASS2  4dBm Bluetooth working frequency：2.4GHz Charging voltage:    DC5V/500mA Working voltage ：DC 3.7V Battery capacity:400MA Music playing time：4H Talking time:8H THD: ≤ 0.1% (3.7V/1KHz/1.8W) Signal to Noise Ratio：≥65 db Speaker parameter: 4Ω3W ф40MM Bluetooth range :10-20m Colour : Red/Blue/Silver/Black/White/Gun metal