Compared with battery calculators, our calculator is with a Type-C data cable, no need to replace batteries frequently. It can be used for about 240 to 300 (depending on each person's usage) with a 150- charge. It also has a solar panel, so you 't have to worry about running out of power when using it . It can also support continuous use for a period of time when the battery runs out Have you ever encountered the trouble of not being to find a pen and paper to record the results of the calculation process? This financial calculator combined with an LCD writing tablet solves that problem The calculator keys are made of high-quality ABS, which feels comfortable in the hand, and the sound is quiet when pressed, which is not easy to disturb others. The "lock" key function can save your important notes and prevent accidental deletion.and effective for financial, family, accountant assistance to 4 function mortgage calculation and tax conversion; Made of durable ABS material. A small portable general- desktop calculator , school, office or shop, do general and note-taking like we do, with multiple financial functions, perfect for adults and students. Gift box design, good gift Material: ABS colour: Black Package Contents: 1 x calculadora cientifica 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.