Our lovely wheaten terrier puppy tore down the blinds and the lace curtain so he could see out the front door's window. The window is plexiglass and is 19" x 55". I figured out that I can apply window film to the outside of the plexiglass, so the dog can't remove it. We'd once again have some privacy from the dairy cows across the road, plus the people who drive by. I needed 2 rolls and bought 3 in case I made a mistake. Then it sat here for a month, while I put off doing the actual work. I was pretty sure the possibility for failure would be high, since I would be the one doing the job. Today, I applied it to this long window. I thoroughly washed it with Windex first. Then I sprayed the plexiglass with soapy water, according to the directions. The dog was in his crate because he wanted to help by taking off with the rolls of film and destroying them. To my surprise, the film is thick and very easy to work with. I was expecting it to be awful, like Saran Wrap (which is the bane of my existence). I peeled it off and applied it to the top 2/3 of the window. Instead of cutting it to fit, I used a utility knife to cut it to fit on the right hand side of the frame. I got this idea from a YouTube video on how to install window film. It looked easy, and it was! By utility knife,I mean this tool that holds razor blades which poke out so a person can use it to cut something. I'm pretty sure only diamonds can cut glass, so no worries there. Remember, I have plexiglass, which is easy to scratch. I didn't care about that because the dog has already scratched up the plexiglass. Really, I'd like a new door ... but I digress and this is cheaper. I had to apply a second panel, and it did butt up right against the first one, and it matched the pattern exactly. The only trouble I had was when I removed the water with the scraper that was in the package, the film moved a tiny bit -- less than 1/16th of an inch -- from the top film's bottom edge. So I removed the bottom piece and did it again. No matter what I did, I still got the gap. This bugged me to no end. When it finally got dark, I went outside to see how the film looked on the door, I didn't even notice the gap. At first I thought it had disappeared by magic. It didn't, but it is not noticeable. I bet it wouldn't be there if I were more skilled or had redone the application until it was 100% perfect. The door looks fantastic. The dog is not happy that he can no longer see out that long window, and probably frustrated because he can't remove the film since it is on the outside of the door. Everyone loves it except for my teenage son who thinks I should sacrifice our privacy so the dog won't get depressed. This was so easy to put on that I didn't miss not having a grid on the liner, which sure would have made it easier to cut to size if I hadn't watched the YouTube videos. I could not have cut a straight line with scissors, from ample previous experience. If a totally inept person like me can put this film on a window, anyone can. The other good news is that a visitor just arrived and he thought I had put stained glass in my front door. This is a really great product which solved a difficult problem for me. I am pretty sure the film will stick to the window because I once applied bubble wrap to a window the same way, and it stuck just fine, through a cold New England winter, until I took it down. Edited to add: Here it is, a year after I installed it, and this product is still great. It hasn't torn, it hasn't fallen off or peeled off, and it hasn't faded. The very cold winter weather doesn't have any effect on it. And the dog is not depressed by not being able to see out the window.