Hex key sets have hexagonal (six-sided) tips that fit into the hexagonal (six-sided) indentation in the bolt or screwhead.The hex key is then turned to rotate the fastener to tighten or loosen it. Folding hex key sets contain multiple keys attached to one handle.Hex keys having tips with a hex ball end allow fasteners to be accessed from multiple angles in hard-to-reach areas.The hex keys can be L-shaped with two arms of unequal length, one long and one short.The short end can reach fasteners in tight spaces while the long end extends the reach of the tool. Rotating a fastener using the long end as a handle provides more torque on the fastener compared to using the short end.T-shaped hex key sets have one long arm with the drive tip at the end and a handle that can provide more torque when rotating fasteners compared to L-shaped keys. Sets come with an assortment of hex keys for a range of fastener head sizes.