locking pliers
Locking pliers, also known as vise-grip pliers, are pliers that clamp firmly onto objects in the way that a vise does. They have a knob at the end of one of the handles which controls the width and tension of the jaws.
A simple procedure is used to operate the pliers. The jaws are placed on the object to be held. The adjusting screw in the handle is turned until the pliers grip the object. The handles are squeezed together to lock the pliers. The release lever on the inside of the other handle is squeezed to remove the pliers.