Nail Clipper - A nail clipper or nail trimmer is a mechanical device used to trim fingernails and toenails. Nail clippers are usually made of metal. Two common varieties are the plier type and the lever type. Both are common household objects. Most nail clippers usually come with another tool attached, which is used to clean the dirt out of nails. A nail trimmer often has a miniature file fixed to it to allow rough edges of nails to be manicured. Nail clippers occasionally come with a pocket knife or a nail catcher. The nail trimmer consists of a head which may be concave or convex. Specialized nail trimmers 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 clipper. Cutting heads which are parallel to the principal axis are made to address accessibility issues involved with cutting toenails. Nail clippers may also be entirely enclosed in a flexible plastic so that it appears less threatening to children, especially those who are afraid of being cut by the clippers. These are manufactured as 'child-proof' nail clippers. The invention of the nail clipper has been attributed to Chapel Carter in the year 1896. - answers.com