Durable Anti-fade keys Unique features of HEAVY DUTY calculators Key Layout and Key Cap Shape Non-slip Structure Perfectly fitted to your right finger for easy typing. With our newErgonomic Step Keysstructure, your calculator matches the contours of your hand instead of requiring you to adjust for the calculator.Unique features of HEAVY DUTY calculatorsExtra Large DisplayLarger display makes more data easier to read.Durable Anti-fade keysKeys are produced by injecting plastic of two different colours. Key markings are plastic, which means they do not wear or fade with use.Key Layout and Key Cap ShapeKeys are ergonomically shaped and configured to match natural finger movements.Non-slip StructureLarge rubber feet on the bottom of the calculator keep it from slipping during operation.Function Command SignsA symbol (+,,×,÷) on the display indicates the status of the operation you are currently performing.Solar & BatterySolar powered when light is sufficient, battery powered when ligh