A C-clamp or G-clamp or G-cramp is a type of clamp device typically used to hold a wood or metal work piece, and often used in, but are not limited to, carpentry and welding. Often believed that these clamps are called "C" clamps because of their C-shaped frame, or also often called C-clamps or G-clamps because including the screw part, they are shaped like an uppercase letter G. However, in fact, they were originally called a carriage maker's clamp, or Carriage Clamp.