Pet Safe Wall Entury Aluminum Door-Puppies, Kittens, & Dogs

This pet door can be installed in many exterior wall materials, siding, stucco and even brick.Features:
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 1/4" (18 cm) Small:
Fits walls 4 3/4 to 7-1/4 (12 cm - 18 cm) thick
Dimensions - 9 3/4" x 13 1/2" (24.7 cm x 34 cm)
Flap Opening Dimensions - 5" x 7" (12.7 cm x 17.8 cm)
Great for pets up to 12 lbs (5.4 kg) Medium:
Fits walls 4 3/4" to 7 1/4" (12 cm - 18 cm) thick
Dimensions - 12 3/4" x 17 1/2" (32.4 cm x 44.5 cm)
Great for pets up to 40 lbs (18 kg) Large:
Fits walls 4 3/4" to 7 1/4" (12 cm - 18 cm) thick
Dimensions - 14 3/4" x 21 1/2" (37.5 cm x 54.6 cm)
Flap Opening Dimensions - 10" x 15" (25 cm x 38 cm)
Great for pets up to 100 lbs (45 kg)