This back panel is recommended to every customer. When in use, it will allow your kitty cat access to their Cat Solarium any time they want to get in. It also keeps the outside weather from flowing into your house and insects outside where they belong. The cat door, made by Petsafe, has a two-way lock. It is easily inserted into the Solarium and can be removed by removing 2 screws with an Allen wrench, which we provide.