The pet doors are made of high quality ABS material, which is durable, strong and easy to clean, ideal for wooden doors such as interior/exterior doors, doors and windows, cabinets. Easy Installation: In the cat door, there is a detailed installation guide to help you install quickly. 8 long screws and 8 short screws are provided, please choose the appropriate screw according to the thickness of the door. The thickness of the cat door can be cut according to the thickness of the door. 4 Switch Modes: The pet door can be adjusted in 4 modes: just out, just in, out and fully locked, easy to control pets' entry and exit. Construction Details: The cat door seal brush strip can reduce noise when closing the pet door . Cat doors are tightly sealed to keep out rain, wind, or pests in your home like mosquitoes. Inside dimensions of flap opening: 18 x 18.5 cm, external dimensions of the frame: 23.5 x 27.5 cm, maximum thickness: 5cm. Suitable for small dogs or cats so they can go in and out freely.