1 Adjustable Door Strap: The simpler way to keep dog out of room with litter box and cat food while still allowing your cat to have easy access. Plus, the handy cat door stopper will prop your door open and prevent your pets from accidentally closing the door. It is also preferred over a dog gate with cat door or cat doors for interior doors. 2 How Dose It Work: The pet door strap allows the door to any interior room to open just wide enough so cats can easily enter or exit, 3 Perfect Solution: It is simple, convenient, and it works! Skip the hassle of a pet gate with cat door. Don't cut a permanent hole to install an interior cat door. It is the perfect solution to dog proof litter box and dog proof cat feeder. 4 Installs In Seconds: Just peel and stick to the door and door frame using the strong adhesive. Adjustable: adjust the width of the door opening wider or narrower to work with the sizes of your kitty & pup.5at the same time keep it narrow enough so dogs (if slightly larger than cat) cannot get in. The pet door stopper prevents the door from closing and serve as a guard to prevent pinched tails (or fingers)! Easy to install indoors, the adjustment range is 20-30c.