many portable alarm clock have light dial that fill the room with blue , green or red light all night , which have be show to interfere with normal sleep . this alarm clock have a dial with a soft adjustable backlight that can be set to a very low level . moreover , if you need a stronger backlight momentarily , you can get a much brighter purple one simply by press the button on top . additionally , I much prefer the Analog face to a digital one , since it be easier to read late at night . highly recommend .