The Pentel Hi-Polymer erasers are high quality, rubber erasers that remove lead easily and cleanly with very little pressure. No smudges, no paper tears and no ghosting. Hi-Polymer erasers do not crack or harden with age and remain soft and ready to use when you need them. Block erasers come with a protective sleeve to keep you and the eraser clean. The block style is perfect for getting into little corners, while the large block erases large areas quickly.