Twilight for Android filters the flux of blue light emitted by your phone/tablet at crucial times, like bedtime, and replaces it with a soft and pleasant red filter.

It can also be set to adapt to the time of the day by adjusting to the sun cycle based on your local sunset and sunrise times.

Twilight for Android is perfect for reading in bed by providing a more pleasant light emission for night reading by giving you to the ability to lower the screen backlight far below the ability of the backlight controls on your screen.