An AAA or triple-A battery is a standard size of dry cell battery commonly used in low-drain portable electronic devices. A zinc–carbon battery in this size is designated by IEC as R03, by ANSI C18.1 as 24, by old JIS standard as UM-4, and by other manufacturer and national standard designations that vary depending on the cell chemistry. The size was first introduced by The American Ever Ready Company in 1911.
A triple-A battery is a single cell and measures 10.5 mm (0.41 in) in diameter and 44.5 mm (1.75 in) in length, including the positive terminal button, which is a minimum 0.8 mm (0.031 in). The positive terminal has a maximum diameter of 3.8 mm (0.15 in); the flat negative terminal has a minimum diameter of 4.3 mm (0.17 in). Alkaline AAA batteries weigh around 11.5 grams (0.41 oz), while primary lithium AAA batteries weigh about 7.6 g (0.27 oz). Rechargeable nickel–metal hydride (NiMH) AAA batteries typically weigh 14–15 g (0.49–0.53 oz).