Thesederwent replacement erasers are designed for use in the smartly designed derwent battery operated eraser this pack of 30 long replacement erasers will let you erases quickly with accurate and precise control once installeda handy tool for all artists the derwent battery operated eraser will make your edits even more effortless with this pack of replacement erasers youll be able to get the most out of your battery operated tool for even longer size 25cm 1 inch30 packreplacements