Locking Pliers
Locking pliers can be locked into a position with the serrated jaw (either flat or curved) around a fastener or work piece. They are particularly useful when the material being handled is difficult or uncomfortable to handle. The locking position of the jaw is adjustable and the same pliers can be used on different sizes of fastener or work material. Your crews may commonly refer to them by the registered trademark of a popular brand, Vise-Grip.