Socket cap screws are high-strength tension fasteners designed for clamping assemblies and are commonly used in tool and die fixture applications. Socket screws, also known as Allen head screws, are available in several head styles and materials. Used in many applications, socket screws are reliable and durable. Socket head cap screws or bolts are manufactured by us in carbon steel, alloy steel and stainless steel grades in 8.8, 10.9 and 12.9 grades.