Push the button for adjustment on the workpiece. Fine adjustment for optimum adaptation to different sizes of workpieces and a comfortable handle width. Self-locking on pipes and nuts: no slipping on the workpiece and low handforce required. Gripping surfaces with special hardened teeth, teeth hardness approx. 61 HRC: high wear resistance and stable gripping. Box-joint design for high stability due to double guide. Reliable catching of the hinge bolt: no unintentional shifting. Guard prevents operators' fingers being pinched. Chrome vanadium electric steel, forged, oil-hardened.