Lock function: A lock button to prevent accidental erasure, switching to the LOCK side will enable the protection function, handwriting cannot be erased. Switching the lock button on the back to the unlock side will make the LCD tablet clear with one click. The built-in battery is only used for the delete function, and Tuya does not consume power, achieving low power consumption and long standby time. Fasten the screw to the battery button so you don't have to worry about the unknown part being swallowed by your child. Functionality: The reusable drawing tablet is suitable for writing, drawing, office memo board, message board and as a communication tool. No more waste paper for graffiti boards or practice paper, protect the environment and save money. LIGHTWEIGHT AND PORTABLE: The 8.5" drawing tablet fits easily in a purse, bag or briefcase so you can use it anytime. Perfect for sparking your and your child's imagination on this drawing board during a car or plane trip. Note: Due to long-distance shipping, some traces may be left on the LCD screen. This is normal, just press the delete button to erase. No battery provided Power supply battery: button battery CR2025*1 Delivery Quantity: 1 Piece Size: 22.4*14.7*0.5cm color: blue Kind tips: 1. Package content: only the above package content, excluding other products. 2. The size is measured manually, please allow 1-2 cm measurement error. 3. Due to different displays and lighting effects, the actual color of the item may be slightly different from the color shown on the picture.