4 Twist Lock: Our indoor outdoor cat door could be set to 4 modes by the twist lock with tabs: only exit, only entry, both entry and exit and fully locked, easy to control your pet. company at the entrance and exit.Size: Outer size 27x23x5.5cm (L x W x H), Inner size: 19.5x18cm"(L x W), suitable for installation on doors and thin walls, suitable for cats lighter than 11kg.Quiet: With the help of magnets and brushes, the panel does not does not come into direct contact with the plastic, which can reduce the noise caused by large cats entering and leaving.The transparent door panel for opening and closing ensures that pets can observe the interior environment and outside at any time.Reduce Your Heating Control Air Conditioning CostsThe doors can't be opened all the time, the cat can come and go freely in the wind, without the heat of the parts of the house from getting cold.Easy to CleanThe smooth plastic housing makes it easy to remove stains brought by your cat from the outside. Note: It is best to use it indoors.L: Exterior size: (W x H x D)27 x 23.5 x 5.5cm Inner size: (L x H)19.5x18cmSuitable for cats under: 11KG