The doggie door with expanding tunnel fits paneled, wood, PVC, and metal doors of 1 3/8'' - 2 1/8'' thick. The large dog door flap opening is 11 1/8”(W) x 16 1/4''(H). Dog door for large dogs are made out of Rugged Sturdy Aluminum, strong and durable for active dogs without worrying about breaking and bitten easily. Granij Color: Black