Add some promotional power to your advertising campaign with this dual power calculator! Measuring 4 1/2" x 5 3/4", this black and silver calculator features a classic design with an eight digit display. You can turn the sound on or off. A great desk accessory for school or for the office, customize this item by adding an imprint of your company name or logo. What a great way to multiply your brand exposure! This calculator uses solar power and includes a battery as well.