This design is a doorstop. It can be used to keep your door fixed in any position. In particular if you have an animal that you want to let pass while keeping your door ajar this model will perfectly fit your need.
It is composed of three files: the base, the screw and the top of the screw. The later two are assembled by a M3 screw of 8 to 20 mm.
You can chose the length of the screw (7 or 9 cm) depending on the distance between your door and the ground. I also recommend to use a chair leg pad between the feet and the ground.