Here is a Super Cool SOUND ACTIVATED LED Hat.  The hat is battery operated (2 triple AA) and can be switched on and off and operates entirely based on sound activation.  They are super fun in clubs and concerts.  This one is a Thinking....  and there are about 12 different levels of light up, there's a battery pack that sits inside the hat, under a cover, and an on/off switch on the inside. They are adjustable as any baseball cap would be and have an on/off switch inside the hat.  They run for a long time on a single set of batteries since they are LED.  The motion action is really cool, see my other listings for about 30 styles in LED light up hats.  I will be out of town November 13 - 20 so can't ship during those dates and also December 2 - 9.  Shop early, make GREAT CHRISTMAS PRESENTS