I was at a concert the other night helping my friend run sound. We brought in all the equipment and began setting up. We put the speakers in place, set up the drum kit, put up the mics and even put the sound board in the back. He plugged this other devise into the sound distribution unit. Right when I was ready to hook up power to the speakers I realized that they were already on. I did a double take when I noticed their were no power cords coming out of the speakers. My friend went on to tell me that he just got a wireless Pa speaker system. It was so cool.