OSALO OS-991ES PLUS II Scientific Calculator With 417 Functions Solar Powered Large Display Desktop Calculator 1. This solar-powered scientific calculator is designed for students and professionals, offering 417 functions to handle a wide range of mathematical operations, from basic arithmetic to advanced calculations in statistics and engineering. Its compact design and dual power supply make it a reliable tool for everyday use. 2. Dual Power Supply: Operates on solar energy with a button battery, ensuring uninterrupted performance in various lighting conditions. 3. 417 Functions: Supports complex operations including fraction calculations, integration, combination and permutation, statistics (with STAT-data editor, standard deviation, normal distribution, and regression analysis), base-n conversions, logical operations, complex number calculations, and engineering symbols. Includes CALC memory, 9 variable memories, 40 scientific constants, and 40 metric conversions (20 conversion pairs) to streamline repetitive tasks. 4. Features a big display with 10+2 digits for clear readability and comfortable typing, reducing eye strain during prolonged use. 5. Compact dimensions (164 x 80 x 20mm) with a slide-on hard case for easy carrying and durability, ideal for school or field work. 6. Statistical Capabilities: Equipped with tools for data analysis, such as standard deviation and regression, making it suitable for math and science courses.