Features: 12-digit Extra large LCD display with punctuation Twin power solar operation automatically switches from solar to battery power in low light 4-Key Memory:includes memory plus, memory minus ,memory recall and memory clear keys Additional keys:include percent key ,make-up key, all clear key,sign change key,square root key,grand total,right shift key,clear error key and switch key Durable hard cover Dimension:6.2''*6.2''*1.5''