Made by Pentel, the ZE-21 Clic Eraser ('Clic' has no 'k') is basically a really long eraser inside a plastic case. After you use up the eraser that comes with it, you can buy refills. Sliding the eraser up and down drives people nuts. The eraser is the high-quality white stuff that removes almost all pencil marks. I highly recommend it for most of your erasing needs.