12-digit heavy-duty printing calculator with equals/plus logic features a large two-color backlit display with negative numbers in red. Design includes large well-spaced contoured keys with PC Touch and left side total key. Prints 4.0 lines per second in two colors. Calculator delivers large print on paper tape. Enter two cost/sell/margin variables the third appears and prints. Functions include tax set and tax +/- four-key independent memory change sign key grand total key item count date/non-add and automatic constants.