Groove Joint Pliers
Tongue-and-groove pliers - also known as water pump pliers, adjustable pliers, groove-joint pliers, arc-joint pliers, Multi-Grips, tap or pipe spanners and Channellocks - are a type of slip-joint pliers. They have serrated jaws generally set 45 - to 60-degrees from the handles. The lower jaw can be moved to a number of positions by sliding along a tracking section under the upper jaw. An advantage of this design is that the pliers can adjust to a number of sizes without the distance in the handle growing wider. These pliers often have long handles - commonly 9.5 to 12 inches long - for increased leverage.
Tongue-and-groove pliers are commonly used for turning and holding nuts and bolts, gripping irregularly shaped objects, and clamping materials.
This design of pliers was invented and popularized by the Champion-DeArment Tool Company in 1934 under the brand name Channellock (after which the company would eventually take its name) but are also now produced by a number of other manufacturers.