[Cat Flap Size]Large Size: External dimensions: 29 x 25 x 5.5 cm (W x H x D); Internal dimensions: 20 x 22 cm (W x H); Suitable for cats up to at 18 lbs, suitable for thickness up to 55 mm from any wall or door. [Simple and good design] The transparent flip cover allows pets to see through the door. The external screen is used for sealing. Brush bars reduce energy loss and quiet action, ensuring that neither the animal nor the owner are disturbed [Easy to Install]Full instructions are included, allowing you to easily install it on windows, doors, cabinets, etc. if you have any questions, do not hesitate to contact us [4 switch modes] Switch - fully closed, fully open, only indoors and outdoors, only indoors and outdoors, easily control the entry and exit of animals from company; [Cat Door] A great solution for allowing your cat to enter any interior room while giving you full control; ideal for entering bedrooms or even food or litter boxes, when they are closed behind the door, dogs