Do you want a cat door but don’t want to harm your doors or windows? The PetSafe Cat Windoor Non-Permanent Cat Door is a great choice. It works in windows with a standard size of 24 ½ by 34 inches wide. It has a secure weather tight design with a 4 way lock to control the coming and going of your cat. When it is taken out of the window, there is no damage left behind. Intended for cats that weighs up to 22 pounds. $100.