The Calculated Industries Gradematic 4000 Black LCD Screen Teachers Calculator is a handheld scientific calculator with a regular key size and LCD display. It is powered by batteries, making it convenient for use on the go. This model is designed for educational purposes, offering advanced mathematical functions for teachers and students. The brand, Calculated Industries, is known for producing reliable and user-friendly calculators, making this a practical choice for those in need of a versatile and efficient calculator for office or educational settings.