These compact power sources fit into watches, hearing aids, and even car keys. With so many button cell battery sizes available, selecting the correct one matters. This 2024 guide breaks down standard sizes, their applications, and includes visual charts for quick reference. A button battery is a small, round, flat cell designed to deliver steady voltage over a long period. Their compact form, lightweight design, and reliability make them ideal for small electronics where space is limited. Tenergy 1.5 Volt Battery Button Cell LR41, ag3 Batteries Equivalent, Ideal for thermometers, Watches, Laser Pointers, Small Toys, Portable Electronics, 20 Count Explore a complete button battery size chart, understand battery codes, and learn how to choose the right one for your device. Button cell batteries, also known as coin cell batteries, are small, round batteries commonly used in small electronic devices such as watches, calculators, and hearing aids. Button batteries, also known as coin cell batteries, are small, round batteries widely used in various electronic devices. They function by converting chemical energy into electrical energy. Explore the smallest battery size, including coin cell and button batteries. Compare dimensions, chemistry, and applications with a practical selection guide.