I had been having a hard time finding something that would block out all the blinding white and other painful screen tones people use these days. And this one adapted it in a way that doesn't just place an overlay over it all and dim what you are trying to read too much. It even changed the white to black, and the black to a light gray so it was gentle on the eyes. many other features like customizing what colours you want things to be, or dimming things. but it's all tailored to YOU. easy toggle on and off for each page you are on. No blanket coat that suits some pages and not others. So that's great. I love it. Thanks for making this. You're a gift!!!! My eyes thank you.