The Electro Luminescent T-Shirt has a built in graphic equalizer panel that is sound sensitive. As the music beats, this special T Shirts equalizer lights up to the beat of the music.It has a fully functional EL (Electro Luminescence) panel with a battery pack that snuggles discretely into a pocket inside the shirt.Each frequency of music will activate a different equalizer bar. Size: 2X-Large Batteries: Uses 2 replaceable AAA batteries. Weight: 0.63 LB