The optional closing cover mounts on the opposite side of the door or wall from the pet door (it will not install over the pet door. A sturdy, ¹/₂" thick polypropylene panel slides down provided aluminum channels over a 14" x 20" opening. If you want this locking cover to be proof against someone lifting from the outside, drill a ¹/₂" hole through the cover and wall on the inside and insert a short dowel.

Recently, Carl has come out with The Big Dog Door for really big dogs. This is among the very largest of dog doors on the market. Not good to share with cats.

Finally, he has released the 'Easy' door which simply swings from a hinge at the top. Close tolerances minimize any air leakage from this design.

Hot Tip: The lifetime warranty even covers chewing!