Mr. Pen standard function calculator is made of a sturdy and premium plastic body, and it is convenient, powerful, and long-lasting..A big LCD screen that displays big numbers makes it easy to read from afar, and aesthetically pleasing..This calculator’s responsive buttons will make the calculation process faster and smoother. Once pressed, the buttons quickly register and display the corresponding number on the screen. The big size of the buttons prevents you from hitting the wrong button..This calculator utilizes both solar power and battery power. As long as you use it in a lit environment, the solar panel will power up the calculator thoroughly..Mr. Pen standard function calculator is designed for many occasions: business, office, home, basic budgeting, school, and more. Use it to assist your personal finance or just for a quick calculation session.