The AA battery is one of the most widely used cylindrical batteries, commonly found in household electronics, toys, flashlights, remote controls, and portable devices. Measuring about 50.5 mm in length and 14.5 mm in diameter, it delivers 1.5 volts in disposable alkaline or zinc-carbon forms, and 1.2 volts in rechargeable NiMH or NiCd versions. Known for reliability, affordability, and availability worldwide, AA batteries provide a practical balance of size and power, making them a universal standard for countless everyday applications.