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.