100 steps checks: displays up to 100 previous calculation steps; big display; key rollover: key operation are buffered, so nothing is lost even during high-speed input; plastic keys; profit margin percent: % key gives quick access to prices and profit, and also delivers add-ons, discounts, ratio, increase/decrease values and regular percentages; super command signs; tax calculation; two way power (solar + battery); solar powered in sunlight, battery powered when lighting is low.