Steel: 31CrV3 47-52 HRC Chromium-plating H: 55 mm Length: 185 mm An L-shaped hex key (also known as an Allen key) is used for working with fasteners that have an internal hexagon shape. L-shaped keys feature two levers in their design: an extended lever for applying maximum force and a short lever for quick rotation. They are also used for working with fasteners in limited space conditions. Their high strength characteristics help prevent damage to the fastener edges. You can also purchase a set of hex keys.