Commercial Desktop Calculator with Equals Plus Logic prints 4. 6 lines per second in two colors. Printer uses a two-color twin spool ribbon. Design features a left-hand total key, extra-large fluorescent display, 12-digit capacity, and built-in metal paper arm. Two independent tax keys allow you to easily compute two different tax rates such as city/county or county/state. Cost-sell-margin keys allow you to quickly and easily solve cost-sell-margin problems by entering two variables, and the third appears and prints. Calculator displays and prints time and date at the touch of a key. Other functions include markup/gross profit margin key, four-key independent memory, Delta percent of change, percent key, change sign key, grand total, item count, date/nonadd key, square root key, backspace key, and automatic constants.