Which fastener is characterized by a cylindrical head that allows for a wrench to be used?

The fastener characterized by a cylindrical head that allows for a wrench to be used is the socket head cap screw. This type of screw features a recessed hexagonal socket in its head, which is designed specifically for operation with an Allen wrench, also known as a hex key. The design enables a greater amount of torque to be applied compared to many other fasteners, making it ideal for applications that require a secure and stable hold.

The cylindrical shape of the head allows for a compact design that facilitates use in tight spaces, where traditional screwdrivers may not fit. Additionally, the socket head cap screw is often made of robust materials, enhancing its strength and durability in mechanical assemblies. The capability to use a wrench effectively aligns well with operations requiring precision tightening and loosening, as it minimizes the risk of slippage that may occur with other head types.