Give your cat its own door! It only takes a minute to install the Pet Patio Door with 4-Way Cat Flap, and you can even take it with you when you move. "4-Way" means that it can be adjusted via a knob to allow: Exit only, Enter only, in-out privileges, or fully locked. There is no assembly required because it adjusts in height (only) from 78 3/4" to 80 5/8" to ensure a perfect fit in any sliding glass door, either right or left opening. The cat flap opening is 6 1/4" square. This cat patio pet door features a draft stopping watertight seal, and is made of unbreakable LEXAN clear plastic with a security lock for added protection.