Sandpaper / Sandpaper

When use sandpaper, we usually cut it to the sizes we need. And just because of this action that normally makes us cut off the grit at the back of sandpaper and further causes inconvenience for the next use, as we fail to know the grit.
Print corresponding graph at the back of sandpaper with watermark as an auxiliary use. This may help users to feel the thickness easily even without knowing the grit.