Kneaded eraser

It is usually made of a grey or white unvulcanized rubber (though it can be found in many different colors, such as green, blue, hot pink, yellow, and so forth) resembling putty or chewing gum.

It functions by absorbing and "picking up" graphite and charcoal particles, in addition to carbon, colored pencil, or pastel marks.

[1] It neither wears nor leaves residue ("eraser crumbs"), however collect graphite and dust more easily.

They can either be washed or thrown away (typically meaning they last for shorter periods of time than the average eraser).

Besides their precision, kneaded erasers are preferred by artists for their long life and ease of cleaning.