Ishua Automatic Electric Pencil Sharpener - Battery-powered / USB Powered Professional Sharpener with FREE 1 Core Sharpener 100% safty and automatic function: The sharpener will automatic idle once the pencil tip has been sharpened within 0.3-0.5mm/0.01"-0.02", provides ideal tip for you and never over-sharpening. Safty design and products, Instantly stop operation when the shaving tray is removed, safe and easy to use if you can do according to our instruction. Operated by USB charging port (included USB cord) or 4-AA batteries (not included).Multiple power source to keep enough power no matter where you go. Sharp durable SK5 steel blade & large easy-clean shavings tray with faster and stable cutting performance. Replaceable Sharpener Core Design - greatly extending the service life. [1 * replacement core included]