D, C, AA, AAA, AAAA, 9-Volt batteries. The AAA battery (or triple-A battery) is a standard size of dry cell battery. One or more AAA batteries are 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 ... More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.