Elera Electric Eraser Kit Automatic Eraser with 10 Eraser Refills (blue) Multi-purpose: Ideal for drawing, drafting, architectural plans, office supply, arts and crafts, etc. Long-lasting & Refillable: Easy to remove and replace. (10 eraser refills are included and the length of the refills is 25mm) Easy to Use: One push button is easy to use for removing marks Effectively: Circular movement and strong motor can erase the targeted areas effectively Battery powered eraser: Required 2 AAA batteries( not included)