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. Key rollover Key operations are stored in a buffer, so nothing is lost even during high-speed input. Plastic keys Designed and engineered for easy operation. Durable metal Faceplate Tough cover stands up to rough treatment. Regular percent Regular percentage calculations. Mark-up All the mark-up capabilities of an adding machine for simplified cost and profit calculations.