A heavy-duty, no-hassle pet-door solution. Insert this unit into the frame of a sliding glass door to allow your pet access to the patio or yard. Installs in left- or right-sliding doors, while allowing them to lock normally. Its flexible UltraSeal® flap system, glass sweep and included weather stripping greatly reduce heat or cool-air loss. Satin-finished aluminum construction with shatter-resistant glass. Spring-loaded height adjusts automatically. Pet height measured at shoulders.