Portable Wireless Speaker GT-1915 It produces a very decent amount of bass and can go extremely loud that make this a little beast, which is nice bass. If you need music, then be sure to pack our lightweight speaker which is easy to hold or carry in a bag for all types of events without any effort. Dual-mode power supply: built-in lithium battery, can be used via USB interface, power supply, or use DC5V USB power supply, dual power supply mode free choice. Smooth Connectivity: The upgraded bluetooth 4.2 version gives the bluetooth connectivity a boost with the simplest methods and drivers upto 40 mm which ensures an effortless function with a year manufacturer warranty and both wired and wireless functions.