PetSafe Freedom Patio Panel Dog Door gives your pet the freedom to come and go through your sliding-glass door. The spring-loaded dog door fits into your sliding-glass door frame, automatically adjusting to the proper height. To keep out the elements, ceramic magnets ensure the flap closes completely. The flap can be locked when you want to restrict your pet's access. For security, these patio panel dog doors feature a reversible lock for left- or right-sliding doors. Features heavy-duty aluminum construction and shatter-resistant, tempered safety glass.