Got this for my bedroom windows, I live in a ground floor condo, and my neighbor takes her dogs out to use the bathroom right in front of my bedroom window. Nice to be able to open my curtains to let light in, while now she can't see into my bedroom at all. The mirror effect is quite subtle, it's not actually noticeable unless you are standing right there looking at it, but it works! I can see out and nobody can see in. It does darken the room a bit, but the relief of privacy is absolutely worth it, and I'm sure it will help keep things cooler in summer, too. I needed to buy 2 rolls to cover my windows. I have 2 large windows, with 4 pains of glass, each 27"x27". It was easy to measure and cut, and apply to windows, but I did struggle with peeling the backs off immensely. I couldn't figure out the tape method, but all the pain and frustration was worth the anxiety relief I now have with my privacy and the issue with my neighbor. The land around our condos is technically a "common area" so it's not like I can yell "GET OFF MY LAWN!" This was much easier to just adapt to the situation with an easy solution rather than begin an argument/confrontation. Wish I had done this years ago! Absolutely recommend. I only gave 4 stars because it was so hard peeling the back off, even if that was my own problem. There wasn't clear instructions on how to do that, I later saw some youtube videos about the tape.