MaterialCarbon Steel Finish TypeSilver [High Quality Material]: Made of high quality carbon steel and CVR, high hardness, not easy to rust, durable , corrosion resistant, super magnetic, solid structure, can ensure maximum stability and service life. [Hexagonal Design]: The internal hexagonal reinforcement design is used to increase the contact area. The inner magnetic sheet is tightly connected to prevent the drill from slipping and increase your work safety. [Three Sizes]: Provides 3 different lengths of magnetic heads: 50mm, 100mm and 150mm. There is also a 150mm magnetic head, suitable for tools that need extensions, easy to install and can meet your different needs. [Easy and Convenient]: There is a strong magnetic sheet on the inside. interior, with a locking mechanism, which is easy to operate and install, convenient and quick to install, greatly improving work efficiency, and suitable for tools. [Wide Application]: Diameter of 6.35mm (1/4’’) shank on the opposite side of the