LED andon and LED stacklight Steady or Continuous operation lights operate by user applying power to the color control wire. These LED stacklights or LED andon lights are ideal for facilities using PLCs or machine outputs with ability to pulse output to control light steady or flash state. These are also ideal for facilities looking for subtle indication without flash distraction. These LED stacklights do not supply audible or flashing integrated control. See our flashing capable lights for options that include steady and audible or steady and flashing capability.