The outer side of the screw head is a hexagonal shape with a round recess. This type of screw is called a hexagonal screw. A special wrench is needed to fix and remove this type of screw. Generally, special hexagonal wrenches are sold in hardware stores. The biggest function of a screw is to fix it, and the hexagonal screw is mainly used for mechanical fixation. The advantage of this is that it is easier to fix without the consequence of thread stripping. It is also easy to remove, which works with the hexagonal wrench.
