These brightly colored finger lasers from Toysmith are easy to use and turn on or off with a switch. Light switch locks in place so lights will stay active until the switch is turned off. Each set includes 4 plastic lights with black elastic bands, which fit most fingers. Each light projects a different color and measures 4 x 0.5 x 0.75 inches. Light colors include red, white, blue, and green. Contains nonreplaceable button cell batteries.