Professional Quality, tested to 10, 000V and insulated to 1000V AC and 1500V DC for live line working. Manufactured from chrome vanadium electric steel, oil hardened and tempered with smoothly ground jaws, joint faces and an accurately formed box joint. 24 position adjustment. The parallelogram-shaped gripping surfaces have specially hardened teeth to 61HRC for positive grip on pipes and nuts. Heavy insulated handles with slip guards for extra safety. Has 'no-nip' feature which prevents handles locking together and damaging users' hands.