Professional Quality manufactured from chrome vanadium electric steel oil hardened and tempered with smoothly ground jaws joint faces and an accurately formed box joint with safety stop. The parallelogram-shaped gripping surfaces have specially hardened teeth to 61HRC for positive grip on pipes and nuts. Self-controlled adjustment on the task simply by squeezing the handles - perfect for frequent changeover to different sized workpieces. Guard prevents the plastic coated handles locking together and nipping user. Sold Loose.