The large and easy-to-use keypad features three memory keys, a percentage calculator and one-touch sign change key. Protect the screen with the fold back cover when in your pocket or bag. The eco-friendly design features dual power operation - solar with a battery backup - and it automatically switches off when not in use. Calculator with large 8-digit display 3 memory keys Percentage and sign change keys Automatic power-off when not in use Dual power: solar and LR1130 battery