Bought these to use for my son's wedding open house. We realized that the hours were not right and that it would not be dark for the open house. However I have turned on about eight of these lights out of the package and all of them worked perfectly. I put one in a balloon last night and when I woke up in the morning it was still lit, although not as bright. Tonight we put some in a couple balloons and put them out in our pool. The kids had a lot of fun playing with them. I put one light in the red balloon and two lights in the green balloon. You can really tell a difference in the balloon with two lights. They are cool to the touch and therefore work fine inside of the balloon. I could see where you could decorate a pool for a party very easily as long as it is dark enough to see the lights. One of the balloons popped and the light sunk to the bottom of the pool. It continued to be lit and actually looked really cool. Even underwater it could be used as a decoration. Overall I was very impressed by these lights and have carried one around in my pocket to show friends. The price cannot be beat and I think they could be a lot of fun at future parties and events.