Door chain

You know how you have a lock on your door to keep people out? Well, if you want to let someone in but you don't want them to come all the way inside, you can use something called a door chain. It's like a small metal rope that you attach to your door frame and the door itself. It lets you open the door just a little bit, so the person outside can talk to you, but they can't come in all the way. It's like when your mom tells you to leave your bedroom door a little bit open so she can hear you but can't see everything you're doing. The door chain helps keep you safe when you're talking to someone you don't know very well or if you're feeling scared.