HIGH QUALITY MATERIAL: The material used in the cat door is very high quality ABS material with smooth surface, which is convenient for your pets to get in and out. PERFECT SIZE: The cat door outer frame size is 20 * 19 * 5.5cm / 7.87 * 7.48 * 2.17inch. The size of the inner frame door is about 16 * 15.7cm / 6.30 * 6.18in, enough size to accommodate your cat. EASY TO INSTALL: The package includes 8 screws, 8 nuts and detailed assembly steps. This large cat flap is easy to install in no time. FOUR-WAY LOCK: The cat door with lock has 4 switching modes. The red and green tabs can be used to adjust the cat flap. They can be set to be indoor and outdoor only, inside and outside only or fully locked and easy to adjust. APPLICATION: All pets that meet this specification can use this cat flap, which can be used in any small area that needs to be installed in the home.