This Texas Instruments TI-82 Graphing Calculator is a reliable tool for any business or office. It has been thoroughly tested and comes with a protective slide cover. The calculator features a regular-sized display and keys, making it easy to use and navigate. Its power source is battery-operated, and it is small enough to be carried around in a pocket or bag. The TI-82 model is designed for advanced calculations, including calculus. It was manufactured in Taiwan and has not been modified.