Upgrade your mechanical pencil with the Berol Automatic Eraser Refills Z-20. With a dozen tubes of three, you will have plenty of erasers to last through all of your writing needs. These eraser refills are designed to fit most mechanical pencils and are a great addition to any writing utensil collection. The Berol brand is known for its high-quality products and these eraser refills are no exception. Whether you're an artist, student, or professional, the Berol Automatic Eraser Refills Z-20 are a must-have for any mechanical pencil user.