The Silverline Box Spanner Metric Set is made from corrosion-resistant steel and supplied with a steel tommy bar. Ideal for reaching small, awkward spaces and for when a jaw spanner is too bulky to use, the hexagonal construction grips all sides of the head and allows you to apply maximum force. Ideal for plumbing and automotive applications, they can be used for everything from accessing plumbing back nuts and removing spark plugs to assembling furniture.