Allen wrench in L shape with a size 1 tip. A hex key is ideal for all types of use by every professional mechanic, plumber, carpenter, electrician, as well as for home use. The hex keys are formed from a single piece of hexagonal rod made of hard steel with blunt ends that fit comfortably into similarly shaped screw sockets. It is bent at 90 degrees, forming two arms of unequal length that resemble the Latin letter "L".