This product is perfect for anyone looking for an environmentally friendly way to do their calculations. Our solar powered calculators are easy to use and require no batteries or electricity. With a sleek design and bright LCD screen, you can easily calculate equations, fractions, and more with the power of the sun
From Wikipedia
Solar-powered calculators are hand-held electronic calculators powered by solar cells mounted on the device. They were introduced at the end of the 1970s.