Some mechanical pencils have an eraser on the end, and as mechanical pencils are refillable they last a very long time, and the eraser will run out. Well below you will find all sorts of replacement erasers from many different brands. We recommend checking the product description for more information on which pencils these fit.
Caran d'Ache Type 505 Single Eraser
Caran d'Ache 505 eraser refill for Madison, Ecridor, 844V1 and RNX.316 pencils.