What type of wrench is used for tightening a round nut with notches?

A spanner wrench is specifically designed to grip and turn round nuts that have notches, making it particularly suitable for tasks involving this type of hardware. The notched profile allows the spanner to engage securely with the nut, providing the necessary leverage to tighten or loosen it effectively. This tool is manufactured to fit the specific shape and size of the notched design, ensuring a precise fit that prevents slipping or damage during use.

In contrast, a socket wrench utilizes detachable sockets that fit various sizes of nuts and bolts but is not designed for notched types. An open-end wrench has a U-shaped opening that allows it to fit snugly around a nut but lacks the necessary design to engage with notched surfaces effectively. Lastly, an adjustable wrench can be used for a variety of nut and bolt types due to its movable jaw, but it is not specialized for the unique shape of a notched round nut, which may lead to difficulty in maintaining a secure grip.