Dual Power: This calculator powers are solar and battery (battery NOT included), the calculator can be used in daytime without battery; please install an AA battery when the calculator is in a weak light or in insufficient solar energy environment Comfortable Big Buttons: This is a calculator with big buttons, very useful. The buttons are large, it will not be stuck easily when using it. Big buttons can be seen more clearly and use it happily Large LCD Display Screen: 12 digits large screen calculator is more useful for large calculations Practical: This Desktop Calculator is a practical and general purpose calcualtor, can meet various computing needs, convenient and easy to use Application: This calculator is general purpose, applies for office, home, school and so on. It is perfect choose