A mechanical pencil is a writing instrument that uses a thin, replaceable lead core instead of traditional graphite. The lead is advanced by a mechanism, allowing for consistent line thickness without the need for sharpening. Mechanical pencils are popular among students and professionals for their convenience and precision. These pencils come in various lead sizes, typically ranging from 0.3 mm to 0.9 mm, catering to different writing and drawing needs. Many mechanical pencils also feature erasers and comfortable grips, making them user-friendly. They are often preferred for tasks requiring detailed work, such as drawing or technical writing.