What is different between ag4 and ag3 batteries?

AG4 and AG3 batteries differ primarily in size and capacity. The AG4 battery, also known as LR626, has a diameter of 6.8 mm and a height of 2.6 mm, while the AG3 battery, or LR41, measures 7.9 mm in diameter and 5.4 mm in height. Consequently, the AG4 typically has a lower capacity compared to the AG3, which can affect their applications in devices. They are not interchangeable due to these size and voltage differences.