16340 batteries, also known as CR123A batteries, are rechargeable lithium batteries that are commonly used in high-drain devices that require a compact and reliable power source. These batteries have a standard size of 16mm in diameter and 34mm in length, hence the name "16340".

16340 batteries have a nominal voltage of 3.7V, which is higher than the voltage of most alkaline and NiMH batteries, making them well-suited for devices that require a higher voltage. They are known for their high energy density, long shelf life, and excellent performance in low-temperature environments.

16340 batteries are commonly used in a wide range of devices, including flashlights, cameras, medical equipment, and other high-performance electronics. Due to their compact size and high performance, they are also a popular choice for outdoor enthusiasts, hikers, and campers who need reliable and long-lasting power sources for their flashlights and other portable devices.

It is important to verify the compatibility of 16340 batteries with devices using non-rechargeable CR123A or RCR123A batteries since they may not always be interchangeable.