Hex key(Allen wrench) and screw
by yamachem - uploaded on October 18, 2015, 12:09 am
This is an illustration of an allen wrench or hex key and an allen screw or hex head screw.
This original image was donated by Pearson Scott Foresman, an educational publisher, to Wikimedia Commons, and is thereby in the Public Domain.
you can see the source URL in the below comment.