EXPRESS YOURSELF: Perfect for festivals, EDM, EDC, raves, DJs, concerts, bars, dance halls, sports games, and parties. SOUND ACTIVATED: LED lights pulse to the beat of any music with varying intensity levels. The built-in sensor detects sound waves—the louder the music, the more lights are activated! The sensitivity wheel lets you adjust the sensitivity. COMFORTABLE: One size fits all (men and women) with an adjustable snapback strap to fit your head perfectly. The cap is lightweight and has no burden for dancing. The detachable screen can be removed to wash and clean the hat. SAFE TO USE: Powered by 2x AAA batteries (not included). The energy source is a cold light LED that is completely safe for your face and eyes.