The Sony SRS-XB21 Portable Wireless Bluetooth Speaker has been designed to be the life of the party. With Live Sound mode, Sony uses DSP technology to spread the music out to a wider audience for a festival-like audio experience. You can increase the coverage drastically by using Wireless Party Chain. It lets you hook up to 100 (optional) speakers together, all syncing to play the same audio. EXTRA BASS gives that audio an additional deep and powerful boost of bass to keep the party going.