These cool color-changing finger lights include removable fiber optic attachments that create ever-changing starry points of light that shoot up to each tip. A very unique effect that the manufacturer calls "Starriness" (is that even a word?). The light pattern of the multiple LEDs varies automatically between various slow "mood" fades and fast flashing patterns that cycle between the colors. These lights do not have a steady-on function. The different plastic case colors of each light also make each light up uniquely. Take off the fiber-optic tip, and you have a traditional LED finger light. Each light uses an elastic strap to fit any finger, and comes with 3 long-lasting AG3 batteries installed. Each light measures about 4.75" long, including the 3.5" fiber-optic attachment.