This items seems virtually worthless for the intended purpose. I use only the
highest quality clean erasing leads in my pencil. This item mostly smeared the
pencil marks rather than erasing.
I judged it to be about as effective as rubbing the pencil marks with a piece of
wood. In fact, I actually tried this and the eraser did not really do much
better than the wood.
The original eraser that came with the pencil was designed too small to be
practical. It is used up too quickly and very soft so it breaks off easily. At
least it worked well as an eraser while it lasted.
These replacement erasers aren't much good for anything except plugging up the
hole to keep the leads from falling out while the cap is removed.
The lowest mark on the rating scale is too high for the performance of this
I have several Zebra M-301 pencils and these replacement erasers work exactly as
expected. They do erase well despite their small size, but are definitely more
suited to small & quick corrections rather than larger ones.