Steel: 31CrV3 47-52 HRC Chromium plating The sets are designed taking into account the features of car repairs and general assembly work. The set includes: - Inch angle keys: 1/16", 5/64", 3/32", 1/8", 5/32", 3/16", 1/4", 5/16", 3/8"; - Plastic holder. The inch hex angle key (also known as an "Allen key") is used for working with fasteners that have an internal hexagon. Angle keys have two levers in their design: a longer one for applying maximum force and a shorter one for quick rotation. They are also used for working with fasteners in confined spaces. High strength characteristics prevent damage to the edges of the fasteners.