If you have a Mac, then it changes the max brightness of your screen, which is perfect for when you're somewhere sunny. It's free to try it (you can see the difference first-hand).
It's only £10 (one time, not a subscription).
-Justin
About Justin Ferriman
Hey, I'm Justin. Every so often, I share the cool stuff (websites, software, products) that I have used or come across. Subscribe and it'll land in your inbox!