Scandvik 41598P Tortuga DimmerDesigned to easily adjust the interior or exterior light level from 0 100% output. Touch the "up" button to turn light on and touch the "down" button to turn light off. Press and hold either up or down, on the included switch, to increase or decrease the light output level to your likeness. Release at any point to maintain the current brightness. If you are leaving the boat, the Tortuga features an exit mode. Push the "down" button two times within 1.