To activate, give it a quick shake to start, plug it into your USB port and watch the magical light show! The lights in the Rocket Lamp with USB Cable slowly transition through a rainbow of colors. Dimensions: Height: 7.12 in. Width: 2.25 in. Cable Length: 54 in. LED Colors: 1 Red, 1 Blue, 1 Green Rocket Lamp does not use batteries; will only work when USB cable is plugged in.