Even if you have a big dog and need an extra large pet door, try not to buy a bigger door than you need.
Q. What is the most common reason a xl pet door gets returned after purchase?
A. The most common reason is incorrect measuring. Many people "eyeball" the size of their pet and/or the area where they want to install a pet door. Those who purchase a pet door based on "guestimates" often end up with a pet door that is either not the right size for their pet, or not the right size for the installation area.