Steel: 31CrV3 47-52 HRC Chromium plating H: 65 mm Length: 210 mm The hex key (also called an "Allen key") is used for working with fasteners that have an internal hexagon. Angle wrenches combine two levers in their construction: an elongated one for applying maximum force and a short one for quick rotation. They are also used when working with fasteners in confined spaces. High strength characteristics prevent damage to the edges of fasteners. You can also purchase a set of hex keys.