4 switch modes can control in and out of fashion by setting the button, thus you dont need to worry about the safety of pet. It is very easy to install that you just need to tighten the screws and ensure its stability. Made of ABS, It is very durable and solid to use. There are three sizes for choice. It is very suitable for pet, including dog, cats, rabbits, etc. Size Details: S (Exterior Size) : 20cm x 19.2cm x 1.5cm/7.87in x 7.56in x 0.59in (Approx.) S (Inner Size): 16cm x 15.7cm/6.30in x 6.18in (Approx.) M (Exterior Size) : 20cm x 19.2cm x 5.5cm/7.87in x 7.56in x 2.17in (Approx.) M (Inner Size): 16cm x 15.7cm/6.30in x 6.18in (Approx.) L (Exterior Size) : 25cm x 23.5cm x 5.5cm/9.84in x 9.25in x 2.17in (Approx.) L (Inner Size): 19cm x 18cm/7.48in x 7.09in (Approx.) XL (Exterior Size) : 22cm x 25cm x 5.5cm (Approx.) XL (Inner Size): 22cm x 20cm (Approx.) Size:S, M, L, XL(optional) Color:Black, White(optional) Package List: 1 x Cat Door 1 x A set of mounting screw