An open-ended spanner is a hand tool used to tighten or loosen nuts, bolts or any other fasteners and is also know as a crows foot spanner. The open ends often sit at a 15-degree angle to the spanner shaft which allows it to be used in confined spaces where there is little room for movement. This type is spanner is a common piece of equipment, found in most tool collections due to the versatile nature of them.
This spanner provides the user with increased grip and torque when turning fasteners. Some have one head, and some have dual heads ranging in size as well as the tool length. The longer the tool, the bigger the head to give the user more leverage for undoing stubborn fasteners and allowing greater torque application.