The PetSafe Staywell Original 2-Way Large Pet Door give your pet the freedom to come and go as they please without interrupting you, if you busy or gone. Style and security for virtually any application. Locking interior security panel for extra security. Magnetic weather tight seal to help prevent energy loss and insects. Made of durable co-polymer. Interior trim with sliding, locking panel. Fully assembled with easy installation. Will assemble in wood and metal doors. Not for use on glass or screen doors. Overall Size = 18 3/8 x 15 3/8.