Pliers extend and increase hand grip. They’re simple levers, pivoted on a joint: by pressing on the handle, you amplify your grip and direct it to the tiny point where the jaws meet.
Each kit contains a pair of pliers in a variety of sizes, jaws, joints, and handles, each suited to a specific task. But for all the differences, there are only three basic types of pliers: locking, adjustable, and non-adjustable.
Locking pliers are mechanically fastened to the workpiece, allowing you to freely pull, twist and even loosen without losing your grip. Adjustable pliers can be sized to fit various openings while keeping the jaws parallel so they can grip bolts or pipe. (Avoid the familiar sliding-joint pliers, which have a figure-eight joint perpendicular to the handle—you could injure your knuckles when the tool slips.) Non-adjustable pliers move around a fixed joint, sometimes on a spring Open the jaws with help.