Frequently abbreviated to AJ, an adjustable spanner is a spanner with a head which can be altered in size by means of an exposed worm screw. This allows one spanner to be used for a variety of nut and bolt sizes, they are available with a variety of jaw ranges, which are usually related to how long the body of the AJ is. It is still a staple of the technicians toolkit, although somewhat superseded by the Quad Spanner which has all the regularly used sizes and the benefit of a ratchet action. They are also known as crescent wrenches in the US.

See Also

• Quad Spanner
• Podger
• Wingnut Spanner