A pencil eraser is a small, often cylindrical piece of rubber or plastic attached to the end of a pencil. Its primary function is to remove pencil marks from paper, allowing for corrections and adjustments in writing or drawing. Erasers come in various shapes, sizes, and colors, and some are designed specifically for different types of pencils, such as graphite or colored pencils. Erasers work by lifting the graphite particles off the paper's surface when rubbed against it. Over time, they can wear down and become less effective, requiring replacement. Some erasers are also available as standalone products, often found in art supplies or stationery stores, and can be used with any writing instrument.