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, & 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 & easily solve cost-sell-margin problems by entering two variables, & the third appears & prints. Calculator displays & prints time & 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, & automatic constants.