Hale ships all Tall Large and larger size screen pet doors with a stabilizer bar.
The Hale screen pet door
attaches to the frame corner making it very sturdy, but this stabilizer bar to add rigidity to their screen door
Because it attaches to the screen frame in the bottom corner, it is already fairly rigidly attached. The stabilizer bar shown here attaches across the frame and also to the pet door to give it even more support. With the stabilizer bar in place the door is attached on 3 sides. This bar is useful if your smaller, aggressive dogs are going to hit the pet door flap at full speed (terriers, we're looking at you!).
Stabilizer bars come at 48 inches in length, and they get trimmed to fit. The bar is typically installed horizontally, although we have had several customers over the years use these vertically in screened porch installations where each section of screen was wider than 48".