Sharp HO EL2139HB 12 Digit Solar and Battery powered Calculator With Puctuation Large 12 digit LCD display with punctuation Cost Sell Margin Keys allow for convenient calculation of cost, selling price, and margins Twin Power Solar Operation automatically switches from solar to battery power in low light 4 Key Memory includes memory plus, memory minus, recall memory, and clear memory keys Additional Features include grand total, percent and sign change keys, answer check function, and kick-stand display