Door blockers are devices that are used to lock or block doors in a specific position. They can be used to hold the door open in a certain place, to prevent the door from accidentally closing or to prevent the door from being opened. Door blockers are often made of steel or aluminum and are designed to be strong and durable. They are often used in public buildings, such as schools, hospitals, and shopping malls, to prevent people from accidentally closing the door when someone is on the other side. Door blockers can also be used to hold doors open in a certain place, for example to prevent a door from hitting a wall or other obstacle.