PetSafe(R) Wall Entry Aluminum Pet Door™ PetSafe(R) Wall Entry Aluminum Pet Doors™ can be installed in a number of different wall materials, including all types of siding, stucco, and brick, accommodating 43/4" to 71/4" thick walls, making it one of the best wall-mount dog doors available. Features a Dual Flap design (one inside and one outside), making for a well-insulated barrier between the outdoors and your indoor room. PetSafe(R) Wall Entry Aluminum Pet Doors™ can be placed anywhere that you have a clear inside and outside wall area. Features: Fits walls 43/4" to 71/4" (12cm - 18cm) thick Double-flap system insulates for energy efficiency Easy do-it-yourself installation kit Aluminum frame with durable plastic telescoping tunnel Slide-in closing panel included Includes slide-in security panel One-year limited warranty Item Specifications: Small: Great for pets up to 15 lb. (6.8kg) Model No: PPA11-10915 Outer frame dimensions: 91/4"W x 13"H (23.5cm x 33cm) Flap opening dimensions: 51/4"W x 71/2"H (13.3cm x 19cm) Cutout size: 6 3/8"W x 10 1/16"H (16.2cm x 25.6cm) Medium: Great for pets up to 40 lb. (18kg) Model No: PPA11-10916 Outer frame dimensions:121/4"W x 17 1/8"H (31cm x 43.5cm) Flap opening dimensions: 81/4"W x 111/4"H (21cm x 28.6cm) Cut-out size: 9 9/16"W x 14 5/16"H (24.3cm x 36.4cm) Large: Great for pets up to 100 lb. (45kg) Model No: PPA11-10917 Outer frame dimensions: 141/4"W x 21 1/16"H (36.2cm x 53.5cm) Flap opening dimensions: 10 3/8"W x 15 3/8"H (26.4cm x 39cm) Cut-out size: 11 7/16"W x 18 1/8"H (29cm x 46cm) Click here to watch the product video.