Dual Power: Solar energy and battery backup power keep desktop calculator working in low light conditions (not including AA batteries) Desk Calculator Large Display: 12 digits display and large numbers , easy to use. Big Button: The electronic desktop calculator adopts a scientific large button design, which conforms to human habits and is comfortable to contact. Basic Calculator - Add, subtract, multiply, divide, backspace, % and . Auto-off when you do not use it about 10 minutes NOTE: Some user may use desk calculator in early morning or night. The screen maybe difficult to read in low light without battery power. Please AA battery for continuous and accurate usage. colour:Black Material:plastic size:15 x 12 x 4.2cm Package Contents: 1 x Calculator Only above package content, other products are not included. Note: Light and different displays may cause color of item in picture a little different from real thing. The measurement allowed error is +/- 1-3cm.