Product introduction this product belongs to the creative ultra-thin card calculator, the design is novel, easy to carry practical using solar power energy conservation environmental protection, is the best choice for electronic promotional gifts The power of the warm prompt: this calculator is solar energy in plenty of sunlight or lamplight is in good condition But because be ultra-thin design, so there is no electrical functions of the design so you can t charge If you live in a work do not have enough sunlight or lamplight do not buy Can t battery does not belong to quality problems And ordinary bank card is the same size can put in the purse, access at any time convenient fashion