A colorful belt fuses two hemispheres to a perfect sphere. It protects the speaker and increases the bass tones when lying on a surface. So it provides massive sound for this tiny device. The speaker comes with a built-in rechargeable Lithium battery and is compatible with most audio devices. The 3.5mm jack is a regular plug for headphones. When pluged-in, the speaker turns on automatically. For stereo sound two BALLO speakers can be connected with a stereo wire.