Adjustable wrenches are referred to as live wrenches, and their opening width can be adjusted within a certain range, which is a tool used to tighten and loosen nuts and bolts of different specifications. The adjustable wrench is a common tool for maintenance workers, because the opening can be adjusted within a certain range, it is easy to use, not only for standard metric bolts and imperial bolts, but also for some homemade non-standard bolts.
The inventor of the adjustable wrench was the Swede Johan Petter Johansson (1853-1943), who invented the adjustable wrench in 1892.
The adjustable wrench is composed of a head and a shank, and the head is composed of a movable plate lip, a dull lip, a plate mouth, a turbine and a shaft pin. The rotating turbine adjusts the size of the plate edge. Specifications are expressed in length × maximum opening width (unit: mm). Electricians commonly use four specifications: 150mm×19mm (6'), 200mm× 24mm (8'), 250mm× 30mm (10'), and 300mm×36mm (12').