The carpenter's pincers have strongly curved jaws to pull out nails. Their gripping surface has also been reduced to a minimum so that the jaws can possibly clamp under the head of the nail and penetrate slightly into the nail to get a better grip. Once the pincers hold the nail, they are used as a lever to pull out the nail. Sometimes a piece of wood is placed under the jaw to protect the wood surface.
Some models have a square opening between the jaws for loosening nuts. One of the arms sometimes ends in a screwdriver, a sphere - to protect the hand - or a crow bar. In the latter case, the arm may be bent outwards because of too much pressure and the forceps were bent.
The pliers are also sometimes used to cut metal wire, but the jaw is actually not sharpened enough for this purpose. It is better to use these thongs. Their mouth is sharper and more flattened than that of the carpenter's pincers. [MOT]