Constructed from heat-treated, impact grade Chrome Molybdenum Steel, with a protective black phosphate coating. These low-profile sockets are lower than standard shallow sockets, making them easy to use even in tight spaces. High contrast and specific size marking for identification. It helps you select the size easier. It comes with a sturdy and convenient storage case. Keep each piece in the proper position. All EMENTOL products meet or exceed ANSI performance standards.