Mini Mobile Portable Bluetooth Speaker System - Antigravity Batteries Thump Box - Transfers sound through the surface it touches! HOOK UP SEVERAL AT ONE TIME! The THUMP BOX is a rechargeable mini blue tooth speaker system that transmits the music directly into the surface you place it on! Uses a patented Sonic Wave Technology that transmits sonic vibrations into most any surface Compatible with all blue tooth devices and features a lit Touch-Pad for easy control Built in microphone allows you to take phone calls while listening to music You can link multiple units together to play at the same time!