This incredible sound activated LED bracelet responds to the power of sound. It pulses to the beat of music with perfect harmony. It will also pulse to your environmental sound based on the volume and scope of the sound. Simply press the on button underneath the center of the Bracelet. Unlatch one end of the Bracelet and then place over your wrist. The Bracelet fits most adults. The Bracelet will then activate upon sound intensity. The louder the sound, the more brightly and intently the Bracelet will pulse. Batteries included.