Plumber wrench

Similar to the action of a Vise Grip plier, its jaw opening is adjusted to width by rotating a threaded ring.

Its advantage is that it grips with significant force without needing to engage a lock nut like an adjustable tongue-and-groove plier.

Like these, it can also be used on nuts, particularly hex shaped, and other flat engagement points.

[2] The plumber wrench was invented in 1888 by the Swedish inventor named Johan Petter Johansson.

It shares some principles with both the Stillson-pattern pipe wrench and the rigid pipe wrench, as well as various forms of adjustable pliers, such as the Vise Grip and "Channelock" tongue-and-groove plier.