(Patented, one of kind - SlideLock hinge) The Kitty Korner Slidelock hinge is NOT some off the shelf continuous hinge. The SlideLock hinge is purpose built and patented. Designed to convert your standard interior residential door into a convenient cat door. (A cat door that locks in open and closed positions) The unique Kitty Korner SlideLock hinge mechanism is designed to lock in either the open or closed postion via its patented interlocking hinge knuckles. The SlideLock also slides up and away from the floor allowing you to swing it open or closed without striking the floor like a standard hinge will. (No worries about timid pets having to push open a flap) The Kitty Korner cat door locks either open or closed; you decide where and when your cat can come or go. (Works on both solid and hollow core doors) The Kitty Korner cat door is designed to work on both hollow and solid core interior residential doors. (Hide the litter box while allowing your cat access. Keeps the dog from raiding the cat dish) The Kitty Korner cat door allows you to Close The Door on the smell while allowing your cat access and keeping the dog out of the litter box. (Sleep with the bedroom door closed again) When used on your bedroom door the Kitty Korner cat door allows you once again sleep with your door closed while letting the cat to come and go as they please. The Kitty Korner cat door is a DIY installed pet door for your feline friend! The Kitty Korner is simple to install and won't change the look of your home. Simply add the Kitty Korner to any hollow or solid door in your home and let your kitty roam free while keeping all the doors closed in your home. Keep larger dogs or animals out of the room where you keep the cat food or kitty litter