Rock out with the Patented THUNDER LED Wristband, our sound-activated band! When in sound-activation mode, the LED will flash to the beat of music. The switch on the side of the clasp leaves the entire face of the clasp open for our SPECTRUM UV Full Color Printing! For all colors, the wristband is clear when the LED is turned off. Once turned on, the LED illuminates the wristband and engraved message in the color of the LED.