Pliers having two pliers legs that cross at a pivot bolt, of which pliers leg is fixed and the other is movable with respect thereto, wherein the pivot bolt is optionally fixable in a longitudinal slot in the fixed pliers leg by toothing engagement in order to set a mouth opening width, by means of engagement teeth formed on the longitudinal slot and one or more mating teeth formed on the pivot bolt. The toothing engagement is releasable by the pivot bolt being pressed down in a first direction of movement and subsequently the pliers legs being moved together, or by the pivot bolt automatically passing over one or more engagement teeth, wherein the pivot bolt moves in a second direction of movement on passing over an engagement tooth. A movement block is provided at least partially on one pliers leg and are effective for some of the engagement teeth, and the movement block comes into effect during a displacement of the pliers legs together, being effective for the second direction of movement of the pivot bolt.