USB Rechargeable Electric EraserBuilt-in with 600mAh lithium battery, fully charged in 2 hours, LED indicator to shown charging status. Do not need to spend extra money to buy batteries2 Eraser Sizes OptionsComes with 86 replacement refills (Diameter 2. 3mm 48pcs and 5mm 38pcs). The bigger one to create thick highlights and the smaller one to erase tiny parts like hair. Easy to remove and replaceStrong Erasing CapabilityCircular movement and strong motor ensure that you can erase targeted areas effectively and precisely. Only slight pressure on the button for accurate etchinUpgrated Handle DesignThe handle adopts ergonomic streamlined design instead of a large rectangular shape, allowing you control the eraser along with maxium comfort. Transparent cover to protect the pen tip or the charging portSuitable for EveryoneLightweight and portable. A good helper for artists, draftsman, architects, designer, students to draw landscapes, animals or to correct sketches or draft