A device, roughly the shape of a pen, into which long thin piece of pencil lead can be placed. A button can then be used to adjust how much of the pencil lead extends beyond the tip of the mechanical pencil, so one can adjust it as the pencil lead wears off through usage. Mechanical pencils usually also have a small eraser at the end opposite the tip
A mechanical pencil, lead pencil or clicky pencil (usually called a propelling pencil in British English; other names include clutch pencil, or Pacer after a Papermate model, a genericized trademark) is a pencil containing an internal mechanism which pushes ("propels") the thin graphite lead through the tip. Like standard pencils, there are also mechanical pencils which have a rubber eraser on the end. Mechanical pencils provide lines of consistent thickness, well suited for technical applications such as drafting and writing