Mechanical pencils have a mechanism which moves the graphite forward, usually by pressing the button at the top of the pencil.
Mechanical pencils shorten the time of writing, drawing and sketching because they don’t need to be sharpened. The mark left by the pencil always has the same thickness, whereas when drawing with a wood encased pencil the mark will get wider as the process of writing or drawing goes on. Mechanical pencils ensure the line stays the same width throughout.
