Energizer AA Battery Packs of 4 Alkaline Battery E91 LR6 AM3 1.5VThe AA battery (or double A battery) is a standard size single cell cylindrical dry battery. The IEC 60086 system calls the size R6, and ANSI C18 calls it 15. It is named UM 3 by JIS of Japan. Historically, it is known as D14 (hearing aid battery),] U12 later U7 (standard cell), or HP7 (for zinc chloride 'high power' version) in official documentation in the United Kingdom, or a pen cell.