It is a app in which you can lower the brightness if your smartphone at very low. You can use this app at the night time or day time as well to keep your brightness low. Here one screenshot at extreme low brightness. In this app you also get some extra features like protection against blue light , and some eye care mode but I don’t think there’s any difference between normal mode and eye care mode. This app also helps you to save your battery life.if I keep brightness low by using this app then my battery life increase about 1 hour or 2 hour. So you should use this app at night wether you are using your smartphone or not this will help you to save battery life of your smartphone.