Casio Desktop Calculator mx-12b-bk. 12 digits. Extra large display: the larger screen makes data easier to read. Two modes of power (Solar + Battery) battery: By solar energy when there is sufficient light, when the light is insufficient. Simultaneous pressing of keys: operations are stored in a buffer, so nothing is lost during the income of high speed. Margin function: All the capabilities of the function of margin of a utility machine adding machine for simplified with cost and percentage calculations. Regular percentage calculations. Plastic keys: Designed and prepared to be of use Easy. Dimensions: 14.7 × 10.7 × 2.9 cm Colour Black.