When considering a pet patio panel, you first need to determine the kind of sliding glass door you have. You can easily install a patio pet panel door into both exposed and recessed doors. An exposed sliding glass door frame is visible and exposed in the interior and exterior wall. You can see the track the door slides into. A recessed frame is flush with or barely visible in the interior or exterior wall. You can't see the track the door slides into. If you have a recessed door, you will need a Patio Panel Kit (not included) to install your pet door.