Carlson Pro Pets Wall Mount Champion Pet Door, Large Double pane Lexan flaps provide insulation and allow the pet to see through the door Training tool provided to acclimate your pet to its new door Features security lock and quick attach stainless steel security panel Incredibly easy installation, expandable tunnel in wall mount version fits walls from 4.75 Inch to 8.25 Inch with no cutting of the frame required Large Opening Dimension 20"L x 13"w. Breed Examples:German shepherd, Husky, Labrador, Collies, Doberman Pincher, Boxer, Golden Retriever, Bulldog, Pointer