PlexiDor Pet Doors are manufactured to be strong, safe, and energy efficient. Each medium, large, and extra large unit comes with a lock and key and steel security plate making it virtually impossible for an intruder to enter your home. PlexiDor Pet Doors do not require costly vinyl replacement flaps. The unique see-through shatter-resistant dual-thermo pane plexiglass panels open with a gentle push and automatically close tightly without banging. Each panel is lined around all four edges with snug fitting, high density, industrial nylon pile weather seal to provide superior draft control. When closed, the panels reduce air conditioning and heat loss. Your dog will love the smooth, quiet and safe doors and you'll love seeing a lower energy bill. Made in USA.