This item is a pet door specifically designed for screen doors, allowing pets to come and go freely. Magnets are built into the bottom of the door, ensuring it closes tightly and doesn't compromise the screen door's primary function. Simply use the lock when you don't want your pet to go out! The door is secured with screws, providing excellent stability. I opened the package once after purchase, but the inner bag has not been opened, so it is a new, unused item. Thank you for your consideration.