Imagine a pet door installed behind a couch or in a utility room. Our Wall Entry Door can be installed in a number of exterior wall materials, including siding, stucco and even brick. Double-flap system insulates for energy efficiency. Easy do-it-yourself installation kit. Aluminum frame with durable plastic tunnel extension. Telescoping tunnel allows for installation into walls. Extension kit sold separately to extend beyond 7.25". Replacement Flap: 4-0113-11. Wall Extension Kit: MPA00-12640.