I bought one of these several months ago and it works great. It only goes on when it's dark and he knocks it pretty good. It's pretty bright as well. He shifted his position once late at night in the bedroom and I happen to wake up. I looked over and there was a flashing red glow on the wall next to him and at first I thought is was a fire. He wears it all the time. The only complaint is that the o-ring to seal the battery dried up and broke into pieces.