3 16 butterfly anchor

A wafer head screw, as the name suggests, has a flat, thin, and circular head, resembling a wafer. The head is usually larger than the screw's body, providing a broad bearing surface that distributes the load evenly and reduces the chances of damage to the material being fastened. The self-tapping attribute refers to the screw's ability to cut its way through the material it is inserted into, forming threads as it goes, hence the term self-tapping.

...