The Knipex 87 01 Cobra Series Water Pump Pliers 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.