Sylvania DOT-it LED H20 Light, Green

Basically, that's all I use mine for. And it works wonderfully. You can spray water directly onto it and, since it's waterproof, nothing will happen. Adheres well to almost any shower wall. Mine is concrete with a coat of paint over it, and it still sticks. And if it ever comes off, you can use one of these to put it back up. They work quite well, too. Also, they have extremely good battery life. Maybe it's because the bulbs are LEDs, or maybe it's due to the short amount of time that I use it (about five minutes, daily). LEDs are also quite bright and will almost never burn out.

Love the waterproof DOT-it. I used it for light in the refugium of my aquarium. I don't trust the little adhesive dot on the back... in my experience, those are never large enough or sticky enough to hold puck lights in place long term... so I've put it in place with superglue gel.

BUT.. even if the glue fails, my tank won't suffer from electrocution be cause it's WATERPROOOOOOF!!!!! YAY!!!!!

I also love the idea of placing the DOT-it H2O in the bottome of a glass vase.