The Knipex KPX003120V01 Cobra® 2 Piece PVC Grip Water Pump Pliers Set are made from chrome vanadium electric steel which has been forged and multi-stage oil-hardened for excellent durability. The gripping surfaces have special hardened teeth with hardness approx. 61 HRC to ensure high wear resistance and stable gripping. A press-button action allows fast and firm adjustment directly on the workpiece. The pliers allow fine adjustment for optimum adaptation to different sizes of workpiece and are self-locking on pipes and nuts to prevent slipping. Their box joint design provides high stability. A reliable catching of the hinge joint ensures no unintentional shifting.