Great extension. Have been using it for a very long time. First I used it to save battery on my AMOLED screen because of the black backgrounds. In the meantime I can't read on white backgrounds anymore. It is much better for my eyes to avoid these bright white backgrounds. Even on my LCD PC screen I use it in the meantime. To be honest - without this addon I would not use this always crashing Android Firefox one minute longer. So far I couldn't find an other browser enabling black backgrounds on Android in a way as this addon does.