Syn Sons: Bluetooth Version:V4.2 Loudspeaker Output:5W Working Range:In 10Metres Gross Weight:512G *-* Battery Voltage/Capacity:1200Mah Battery Charging Voltage:5V /500Mah Play Time Values For Speakers :3-4Hours *-* Built-In Microphone For Hands-Free Calling Function Enables Users To Answer An Incoming Call Without Delay *-* Compact & Metal Enclosure] About The Size Of A Ring Box This Speaker Fits Into Pretty Much Any Pocket Or Bagour Jacket Pocket Or The Small Side Pocket Of Your Backpack So You Can Take Your Sound Literally Anywhere You Want.