The Casio FX-992S Scientific Calculator from the 1990s is a handheld device powered by solar energy, making it environmentally friendly. This calculator, made by the reputable brand Casio, features complex trigonometric functions and an LCD display for easy viewing. With its compact size and regular key size, this calculator is perfect for on-the-go use in offices or for students studying math and science. The Casio FX-992S is a reliable and efficient tool for solving complex equations and calculations with ease.