• Suitable for most jobs on metallic tubes • Self-locking function in both directions • Strong chain made of tempered special steel • Jaws and body in forged hardened steel • Double sided tooth system for ratchet-like use • Maximal tube capacity up from 38 mm (1-1/2") to 305 mm (12") • Standards: US Norm GGG-W-651, Type I Class B, UNE 16555