Normally it would not be cool to review our own product, but we are making an exception since I use mine daily. I have a glow-in-the-dark set that sits on my nightstands in my bedroom. I turn on my lamps for about an hour at bedtime, and the lamplight charges them to last through the night. In the middle of the night, when I want a drink, I can easily see the shape of my water bottle on top of the coaster. The green glows too bright to be beside my bed, so I went with the blue. The glow-in-the-dark yellow is a mellow brightness too. My tip to share is to make sure you don't have your drink vessel on top of the coaster while it is charging. The coaster charges with a lass/water bottle on it, though with nothing on it charges it more.