Built to your flap dimensions: Pick a flap width and height combination that the stock sizes don't cover Wall thickness 4.5" to 7.5": Same tunnel range as the standard wall mount, so measure your wall before ordering Two colors: White or black aluminum framing to match your siding or interior Custom flap range: Flap widths from 4" to 18" and heights from 5" to 40", in roughly 2" to 5" increments Made in USA, locking cover included: Each unit is built to order in the USA and backed by a 3-year warranty The Custom Dimension Liberty Pet Door for Walls is the build-to-order version of our through-wall pet door. Pick it when the five stock sizes on the standard wall mount don't match your pet or your opening.The aluminum frame and clear vinyl flap are rated from 0°F to 115°F, with the same magnetic seal and weatherstripping as the stock model. Available in white and black, with a locking cover included. Flap widths run from 4" to 18" and heights from 5" to 40", in discrete option steps rather than free entry.Before ordering, measure two things. First, wall thickness: must be between 4.5" and 7.5". Second, the flap opening your pet actually needs. A flap should clear your pet's shoulders comfortably and let them step over the bottom without crouching. If the stock small/medium/large/XL/XXL sizes work, the standard wall mount ships faster and costs less.Made in the USA and backed by a 3-year warranty. Custom builds add lead time, so order early if you have a project deadline.