 The alkaline battery in this size is also known by Duracell type number MN2500 or MX2500 and Energizer type number E96.Historically its consumer electronics use was very limited, and only since the 2010s has it made its appearance in the stores where one would buy its more common AAA relative.This battery size is most often used in small devices such as laser pointers, LED penlights, powered computer styluses, glucose meters, and small headphone amplifiers.