The Plexidor PDDOORMDSV Silver Door Mount Pet Door Unit - Medium uses unique shatter resistant, dual thermo-pane Plexiglas panels that open with a gentle push and automatically close tight without banging. Using a snug-fitting high density nylon weather seal, the Plexidor PDDOORMDSV door panels are designed to provide superior draft-control, keeping heating and cooling in the house. The Plexidor PDDOORMDSV interior and exterior frames are made from heavy duty anodized aluminum that won"t rust, bend, crack or warp. Features: * Rigid, high-impact, insulated and shatter-resistant panels do not require costly vinyl replacement flaps and create a window for your pet * Panels open smoothly with gentle push and close automatically allowing large and small animals to use the door with ease * Designed for doors that measure 1-3/4-inch, which is the thickness of a standard exterior house door * Anodized aluminum interior and exterior frames won’t rust, crack, or warp * Perfect for animals that weigh up to 40 pounds * Keeps out unwanted guests with cylinder lock * Cut Hole of 11-1/2-inch wide x 13-1/2-inch high * Overall: 13-3/4-inch wide x 15-1/2-inch high * Opening of 9-inch wide x 12-inch high * Security with lock, key and steel security plate * No replacement flaps required * Highest energy efficiency What"s In The Box: * Plexidor PDDOORMDSV Silver Interior and Exterior Frame * Installation Instructions * Mounting Hardware * Steel Security Plate * Two Keys * Lock