Nail clippers are usually made of stainless steel but can also be made of plastic and aluminium. Two common varieties are the plier type and the compound lever type. Most nail clippers usually come with another tool attached, which is used to clean dirt out from under nails. A nail clipper often has a miniature file fixed to it to allow rough edges of nails to be manicured. A nail file allows for removal of any excess nail that is jagged or has been missed. Nail clippers occasionally come with a pocket knife or a nail catcher; the multi-purpose nail clipper was invented by Hungarian inventor David Gestetner. The nail clipper consists of a head which may be concave or convex. Specialized nail clippers which have convex clipping ends are intended for trimming toenails, while concave clipping ends are for fingernails. The cutting head may be manufactured to be parallel or perpendicular to the principal axis of the cutter. Cutting heads which are parallel to the principal axis are made to address accessibility issues involved with cutting toenails.