Tear it / Eraser

The paper tube of eraser always keep dirty and crappy after use for a while,
it becomes the source of dirty in our pen box.

just carve teeth on the paper tube,each part of the tube can be easily
and tidily tear off so that the new part of eraser can be used,
the tube will no longer extend out and get crappy.
Eraser always keep as tidy as new, and our hands can always keep clean.