Add some sparkle to that flower garden you plant every summer with the Glow Stone a unique lighting accessory that looks like an ordinary rock by day, but lights up brilliantly at night when it detects motion. The Glow Stone is battery powered, so there's no need to run cables. And because it only lights up for 15-30 seconds when it detects movement only when it's dark out it's incredibly energy efficient. Use one or more Glow Stones to liven up outdoor parties and barbeques.Setup is easy. Simply install four C batteries (sold separately) and then place it in a secure spot in your yard. Make sure the side of the stone with the motion/light sensor is positioned toward the area that gets the most traffic. Motion sensing range is 12 feet. The Glow Stone is portable and can easily be moved around as you see fit.