12 digit calculator is perfect for the everyday advanced user, especially in a busy office setting. Professional heavy duty durability is perfect for power users. You can count on the fast and reliable 4.8 lines-per-second ribbon printer. Professional keyboard with sculptured keys were designed for fast and comfortable operation with contoured Plus/Equal and Minus/Equal keys. Other functions include: mark up key for calculating cost-sell-margin calculations, percent changes, and automatic add-on/discounts calculations, automatic tax keys, constants in multiplication and division, grand total key, change sign key, large-size add and subtract keys, fully selectable decimal settings, date/non-add key, item count, average key, selectable rounding switches and two independent 4-key memories. AC Power.