The pet door can be set to 4 modes by the switches with tabs: only output, only input, both input and output, and fully locked, easy control of your pet’s input and exit. This freewheel door offers optimal protection against draughts with a special seal and a magnetic closure, is extremely quiet and The transparent flap lets your pet see through the door. This pet door is suitable for windows, doors, cabinets, panels and walls etc. and can be installed in doors and walls with a thickness of 2-5 cm. SIZE — S: Outer Size: 19.7 x 19 x 2 cm (H x W x D), Inner Size: 17 x 16 cm (H x W); M: Outer Size: 19.7 x 19 x 5.3 cm (H x W), Inner Size: 17 x 16 cm (H x W); L: Outer Size: 25 x 23.5 x 5.3 cm (H x W x H). D), Inner Size: 21 x 19.5 cm (H x W);XL: Outer Size: 28 x 25 x 5.3 cm (H x W x D), Inner Size: 24 x 21 cm (H x W). The cat flap surface is made of ABS material, weather-resistant, smooth and durable.