The DogWalk doors are made of durable aluminum construction.   Included with the door is a security panel that locks into place.  This panel is made of Makrolon, a durable polycarbonate.  The flexible flaps are made by Bayer High-Tech Plastics.  The flaps carry a limited lifetime warranty, and the door itself has a 3-year warranty. 

The DogWalk Door Mounted pet doors are self-framing (lines and covers the cut through the door) that range in thickness 1 1/4" to 2 1/4".  For thinner doors you must shim around the opening to create a thickness of at least 1 1/4".  The self-framing "tunnel" is an extension of the interior and exterior frame, and will compress together to fit tightly to your door.

Special Note:  The flaps are guaranteed for life, however, if they are chewed, they are not covered by the warranty.  In order to replace the flaps in event of chewing, it is necessary to take apart the frame to replace the flaps.

Also see: MaxSeal™ Door mount pet doors for top quality, superior insulating dog and pet doors.