PetSafe Smart Door Wall Kit - Large
Fits Walls 3 1/2" to 7" thick
Comes with all hardware needed

This wall version of the Smart Door has an interior flange piece with a tunnel extension.  This tunnel assemble will fit walls from 3 1/2" to 7" thick.  There are no additional tunnel extensions available for the Small Smart Door.  The Large Smart Door does have the option to add additional tunnel extensions for thicker walls.  This electronic door is not recommended for cats as the flap may be too difficult to push through.

Large PetSafe Electronic Wall Model:
Explanation of components that are available