Large Keys Easy-to-read large clear 12-digit display. Great design comfortable touch raised buttons increased pressure sensitivity. Two-way Powered :Solar and Battery. Automatically Power off. Color:Black Extra Large display:Larger display makes more data easier to read. Two-way power (Solar + Battery):Solar powered when light is sufficient, battery powered when light is insufficient. Plastic keys:Designed and engineered for easy operation. Tax calculation:Automatic calculation of price plus tax, price less tax, discount, selling price, tax amount, discount amount, and margin amount. Regular percent:Regular percentage calculations. Mark-up:All the mark-up capabilities of an adding machine for simplified cost and profit calculations. Function command signs:A symbol (+, -, �, �) on the display indicates the status of operation you are currently performing.