Patio Pet Doors are narrow inserts that are aluminum, or vinyl frames with the top having glass and the pet door at the bottom. These units sit in the main channel that your slider follows. Most customers will open their sliding door; install these inserts into either the left or right side of the opening. Their sliding door can then open and close to this unit.
Patio Inserts can have dual pane glass at the top or more commonly, single paned glass. Their are several types of pet door opening available for the bottom portion.
This is a great solution for cats and dogs, but remember, using a patio pet door will decrease the opening space that you can use. For this reason a vast majority of customers use units that can easily be removed (temporary models)and require no hardware when installing.