Perfect Halloween T-shirt. The T-shirt lights up and moves to the rhythm of sounds (music, voices, etc). Featuring the latest technology this is by far the coolest shirt for your next sporting event, party or dance club! The LED panel on the front of the shirt feels like a thick iron-on and is powered by 4 AAA batteries. The small battery pack or controller sits in a hidden pocket on the inside of the shirt so it is not noticeable to others or can be clipped onto your pants or belt for a better fit. This shirt is machine washable.