Pincers are a hand tool used in many situations where a mechanical advantage is required to pinch, cut or pull an object. Pincers are first-class levers, but differ from pliers in that the concentration of force is either to a point, or to an edge perpendicular to the length of the tool. This allows pincers to be brought close to a surface, which is often required when working with nails. Pincers are primarily used for removing objects (typically nails) out of a material that they have been previously applied to. Carpenter's pincers are particularly suited to these tasks. Sharpened pincers are also used to cut away natural calluses, also called chestnuts, from a horses body. Further use of pincers is the trimming of the edges of horses hoofs. If the pincers have perpendicular cutting edges, the pincers are often called end-nippers or end-cutters. They're often used in jewelry making, for trimming flat wire or cutting off the end of an ear stud. Pincers, often red-hot, have also been used as an instrument of torture since ancient Roman times or earlier. Pliers are a similar tool with a different type of head used for squeezing, rather than cutting and pulling.