Our LED EL T-shirt is made of cotton. It has an electro-luminescent panel (EL) across the front that reacts to music and and 'pump' in time with whatever you are listening to. It also gives a visual rhythm guide to others. It is powered by a battery pack that put within inside of T-shirt. And the EL panel canbe removed and replaced, its interface is universal, you can use the other EL panel to replace it. Stylish and convenient. Walk into a disco, party or nightclub with our shirt on and the bars on the equalizer start jumping up and down with the beat of the music in real time!! Stand out from the crowd!