The Citizen SR135N is a solar-powered calculator with a large, two-line display. It can calculate statistics including standard deviation, mean, and regression, and has memory capacity for up to 99 calculations. It also features an auto repeat function, backspace key, and a convenient percent key for quick calculations. The calculator is powered by a solar cell, and the keyboard is designed to be intuitive and easy to use. The large LCD window displays up to 10 digits and two lines of data, and the solar power ensures that the calculator is always ready to use.