18350 batteries are a type of rechargeable lithium-ion battery commonly used in small electronic devices that require a compact power source. The number "18350" refers to the battery's physical dimensions: 18mm in diameter and 35mm in length. While they have a lower capacity than larger lithium-ion batteries like the 18650 and 21700, 18350 batteries are highly sought after for their small size and portability. They are commonly used in applications such as flashlights and other small electronic devices. Due to their size, 18350 batteries often require specialized chargers to ensure safe and proper charging. They are also available in different chemistries, including high-drain and low-drain, depending on the intended application.