It did make difference in blocking the sun in a small arched window that I was unable to get a shade to fit.
Using for rv windows
Was a little hard to put up but easy to cut and it has made a huge difference in the temperature in our room by 10+ degrees.
This product started out great. The only thing that wasn't mentioned was that in direct sunlight it shrinks and peels off the window. **First day"I really regret purchasing this. Will have to find another to black out windows since husband work nights.
We found this to be an easy non-permanent solution for our baby's room. A bonus has been that you can take them down and put them back up several times, since we recently sold our house and had to be able to quickly remove the film for pictures/showings/etc.