Kokuyo 5-Sided Eraser (Mirikeshi). This eraser comes with 5 edges of different widths designed to erase small writing, especially in planner and notes. Sometimes a standard eraser might accidentally erase multiple lines at the same time, but this eraser was designed to erase precisely. The numbers on the flat ends of the eraser designate the width (which can also be measured using the ruler on the plastic cover). The edges range from triangle (pointed), 3mm, 4mm, 5mm, to 6mm. The eraser erases nicely, and it's a convenient tool for students or anyone who takes lots of notes.
About Kokuyo:
Kokuyo started in 1905. Their mission is to solve the small problems people encounter in their work and daily lives. Many products from them come with a small clever twist to improve an existing idea.