PlexiDor Pet Doors do not require costly vinyl replacement flaps. The unique shatter resistant dual-thermo pane Plexiglass panels open and close with a gentle push and automatically close tight 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. So whether you live in the hot desert climate of Arizona or in the frigid cold of Alaska, PlexiDor will save you money every month. Your dog will love the smooth, quiet and safe doors and you'll love seeing a lower energy bill.