This dual-powered calculator works with bright sunlight or one Aa battery (not included), automatically shuts off to conserve energy insert one Aa battery for consistent, precise use. It features a 12-digit display, making it ideal for complex calculations, suits business professionals, manual laborers, teachers, students, anyone who needs to perform regular calculations. Designed with large, non-stick plastic buttons made from durable new materials, the layout follows natural hand-use habits for comfortable typing. It also has a large, easy-to-read upright screen that is convenient to carry. You will receive two functional calculators in this set: one basic standard model and one upgraded model with a root function button.