Abstract: The application relates to a pair of pliers (1). More specifically the application describes a pair of single-handed automatically self-adjusting water-pump pliers for clamping or gripping a workpiece. The pair of pliers comprises a first and a second handle (2,3), each handle comprising a jaw portion (8,9), a neck portion (6,7) and a handle portion (4,5), a spacing means (10) between the handle portions (4,5) for adjusting the opening width of the jaw portion (8,9); and the two handles (2,3) are pivotably and slidably connected to each other by means of releasable locking means (13).