Pull-out writing board: Flexible LCD writing board with no blue light and no radiation, designed to protect your eyes. Equipped with a stylus for writing. Other hard objects may be used but are not guaranteed for writing performance. Solar and battery power: Each unit includes a CR2032 coin cell battery and a solar panel for long-lasting battery life, providing reliable power supply. Handwriting pad lock function: The back of the calculator features a lock switch. In unlocked mode, the LCD screen can be cleared by pressing the clear button. In locked mode, the content remains protected and cannot be erased by pressing the clear button. Compact size: Product dimensions are 4.8 x 3.6 x 0.59 inches, weighing 3.8 ounces. Its small and lightweight design makes it portable and easy to carry. Eco-friendly and healthy: Includes a reusable writing surface with no paper, dust, or ink required. Can be rewritten over 50,000 times, helping reduce paper waste. Color: Black Material: ABS Package Contents: 1 x Scientific Calculator Note: This package includes only the items listed above. Other accessories or products are not included. Note: Slight color variations may occur due to lighting and display differences. Measurement error allowed is +/- 1-3 cm.