Size M: Outdoor size: 19 x 20 x 5.5 cm (L x HXT); Interior size: 14.5 x 15.5 cm (L x H); cutting size: 16 x 17 cm (L x H ); Suitable for cats weighing up to 16 lb, suitable for any wall or door up to 50 mm thick; Chat door: an excellent solution to allow your cat to access any interior space while giving you total control. Perfect for accessing the room or even accessing food or litter when kept behind closed doors to keep the dog and children away. Simple and good design: the transparent flap allows the animal to see through the door. The outdoor screen is waterproof. The brush strip reduces noise when closing the door. Easy installation: complete instructions allow easy installation in windows, doors, cupboards, etc. 4 switching modes: switches go out only, light up only, light up and go out, and completely locked, easy control of the entrance and exit of your pet. your pet practical access to food, water or litter behind closed doors. With this catter, your cat will be satisfied