Ideal for use in secondary schools the Sharp EL-W5531 Scientific Calculator features 420 mathematical functions, allowing you to quickly and easily tackle a variety of statistical, trigonometric and numerical equations. Powered by a single LR44 battery, the EL-W5531 boasts automatic power saving through Auto Power Off. Highly durable, this calculator has tough plastic keys in addition to a protective case to help prevent scratches and negate fall damage.