Pull-out writing board:Flexible LCD writing board, no blue light, no radiation, escort for your eyes. Equipped with a stylus for writing and can also use (hard objects other than stylus and cannot be used for writing). Solar and battery dual power supply: Each product has a CR2032 coin cell battery and solar panel, dual power battery life, can meet . Handwriting pad lock function: the back of the calculator has a locking function, in the unlocked state, the LCD writing screen of the handwriting pad can be in a state of clearing comments, and in a locked state, after writing, pressing the clear key cannot clear the written content. Small size: The size of the whole product is 4.8 x 3.6 x 0.59inch,3.8 ounces, which is very small and can be carried around without taking up space. Health and environmental protection: comes with a handwriting board, paper, no dust and no ink. It can be repeatedly written more than 50,000 times, reducing paper consumption. color:Black Material:ABS Package Contents: 1 x scientific calculator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.