Iwako makes a traditional Japanese elementary school backpack eraser. They come in red and blue. We have seen two shades of blue for this Japanese eraser. The darker blue, no longer available, and the lighter blue which is the eraser that we currently have in stock.
The backpack Japanese eraser comes in a Iwako series of items that Japanese school children need for school. The photo on the left is the actual backpack or "randoseru". They are sturdily built and designed to last the full 6 years of elementary school.