I bought three of these, one each for myself and my two children, and when they arrived, only one out of the 9 LED elements had a full battery charge. Of the remaining 8, 7 of them were weak, with the blue LED being VERY faint if lit at all, and one of the LED discs was fully dead and wouldn't light up at all. I'm not sure how I'd go about replacing the batteries, or even the modules themselves, but I'm kind of disappointed that the LED elements were so undercharged straight out of the box.