Wondering how to add a doggie door or cat door to a screen door These screen mounted pet door adapters enable the Pride Pet Doors to be installed in a screen frame patio panel up to a ? inch in thickness. This does not include the pet door or cat flap you must purchase the Pride Pet Door separately if you have not done so already. Available in all pet door sizes, this pet door adapter is the sturdiest way to support a screen door for larger, more active dogs. It is supported by the screen framing on two sides, ensuring stability.