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. 
 

Common use names 

• 239 (VERTA)

• M24F (U.S.A) DURACELL

• AM- 4 (JIS)