Do you have a big cat? You may need a larger door. The Large Cat Door is made to handle cats weighing 15 lbs or more. The door’s opening measures 9″ H x 8.25″ W, compared to the standard door: 5 3/4 x 5 3/4″ . Click on the image to get a better view. In the image, the top door is a regular cat door, the bottom is the larger cat door. After you pick out the package you want, then add the larger cat door. We will take care of the rest.