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.
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).